How to Fix a Leaking Pond

TLDR

Start with what you already know: whether the pond ever held water, approximately how much it drops, and whether you add water to keep it full. Compare the loss with weather and inflow, then investigate soils and any specific structural defect. Soilfloc may fit suitable soil-seepage conditions with water in place; exposed-soil repairs may involve compaction, bentonite, imported soil, or a liner. The correct choice depends on the diagnosis. Optional measurements and soil reports help, but you can ask Natural Waterscapes’ team for assistance at any point.

A leaking pond deserves a repair matched to the reason it loses water. This guide follows the existing-pond decision from the owner's first observations to treatment selection and verification. You can start with an estimate, use Natural Waterscapes’ self-service tools, talk with Natural Waterscapes’ team, or combine those approaches.

Start with an estimate and choose how much help you want

You do not need to finish a monitoring project before speaking with the Natural Waterscapes team. If you already have a good sense of the loss, start with an approximate drop in inches and the period over which it occurs. If you are unsure, say so. That opens the conversation; it does not claim to measure seepage precisely.

Tell the team whether you add water to maintain the level, where it comes from, and approximately how often or how long the pump runs. Clarify whether the reported drop occurs while pumping or when the pump is off. A nearly steady water level can conceal substantial replacement-water use.

Soil information is optional at this stage. Enter a soil description if you know it, or use the leak evaluation tool and provide the link to the completed report. You do not need to select the highest or lowest conductivity from multiple horizons. Interpreting those layers belongs in the assessment, not in a compulsory homeowner calculation.

Staff assistance and self-service remain available in parallel. You can explore the information yourself, speak with Natural Waterscapes’ team, or do both. Neither a completed checklist nor a particular level of uncertainty is required to ask for help.

Use an optional repeatable water level record

For a fixed dock that does not move with the water, mark one safely accessible reference point and measure vertically down to the water surface. Use the same point and units each time. A larger distance below that mark means the water level is lower. A floating dock cannot provide that fixed reference.

A securely installed staff gauge is another option. Record the scale reading at the water surface, along with the date and time. Weekly observations are a practical starting point for a homeowner, or select another interval that fits the situation. Record rainfall, pumping changes, or other observations when known; unknown entries are acceptable.

This optional record improves the context for a recommendation and can continue after treatment. It is not a mandatory waiting period. Reservoirs and projects requiring quantified performance may need a more detailed observation plan than a homeowner's weekly log.

Use the pond history to direct the investigation

A pond that never held water properly

When a pond has never filled or retained water as expected, Natural Waterscapes examines the original soils and construction methods closely. Important questions include whether the basin intersected a permeable layer, whether suitable material was available, and whether the contractor placed and compacted it correctly.

The water supply also needs review. A basin with a limited contributing watershed may not receive enough water to meet its intended use even after seepage is reduced. A successful plan addresses both retention and supply.

A pond that held water for years before developing a leak

A new leak after years of satisfactory performance directs attention toward a change in the structure or a newly connected flow path. Natural Waterscapes commonly investigates animal burrows, decaying roots, damaged outlet pipes, and failed standpipe connections, particularly in embankment ponds.

Natural Waterscapes’ inspection starts along the downstream toe, or base, of the dam. Wet spots, flowing seepage, or unusually lush vegetation can identify areas requiring closer investigation. Natural Waterscapes then inspect the crest for settlement, slumps, animal activity, and other visible changes, while evaluating whether the observations could connect to the downstream wet area.

Outlet structures deserve separate attention. Water can escape through a damaged pipe or joint, or travel along the outside of a conduit where soil contact and seepage control are deficient. An old steel pipe may have corrosion; a PVC assembly may have a broken or improperly made connection.

One outlet failure Natural Waterscapes investigated involved a PVC pipe cut at an angle and inserted into a gasketed fitting. The connection appeared seated, but the gasket did not form a complete seal. Details like that explain why an apparently intact outlet still needs investigation.

Check whether the supply changed before assigning a new defect

An owner may accurately recall that the pond stayed full for decades even when some seepage was always present. A reduction in spring flow, runoff, or supplemental pumping can expose that loss. Natural Waterscapes compares the history with the weather and operating record while investigating structural changes; neither explanation should be assumed from the phrase it used to hold water alone.

Recognize signs that require an urgent dam response

Natural Waterscapes treats active flow carrying sediment from an embankment defect as especially concerning. Internal erosion, often called piping, can remove soil from within a dam or its foundation. ASDSO identifies muddy seepage, soil boils, and developing sinkholes as serious warning signs. New deformation or a rapid change in seepage also warrants prompt professional assessment. Clear water alone does not establish that a dam is safe. [3]

When failure may be developing, the operator should follow the emergency action plan and contact the responsible dam safety professionals and authorities. Active erosion, unstable ground, and potential downstream consequences take priority over a routine product application.

Temporary measures Natural Waterscapes may consider target a known opening where pond water enters a defect on the upstream side. They are professional stabilization measures selected for the particular situation. Blocking a downstream seepage exit or a designed drain can interfere with pressure relief and is not a substitute for repairing the source of the problem. [3]

Establish whether the water loss exceeds the expected water balance

Water level alone does not identify a leak. A pond can fall because evaporation and withdrawals exceed rainfall and inflow. It can also maintain its level while leaking if inflow continually replaces the escaping water. The useful question is how the observed change compares with the expected balance over the same period.

The governing relationship is straightforward:

Water entering - water leaving = change in stored water.

For a pond or reservoir, inputs can include rainfall directly on the water, watershed runoff, stream inflow, groundwater inflow, and pumped additions. Outputs can include evaporation, withdrawals, controlled releases, spillway discharge, and seepage. Storage is the volume held in the basin. USGS water budget studies account for these flows and storage changes when investigating water availability. [1]

Start with rainfall and evaporation

Natural Waterscapes begins many pond consultations by comparing precipitation and evaporation for the location and relevant time period. This establishes whether the weather alone suggests a net gain or loss from the water surface. The owner's observations then provide context: when the decline began, whether the pond previously held water, how quickly it falls, and whether a wet area has appeared below the dam.

Many owners who contact Natural Waterscapes describe substantial losses rather than a small difference that is difficult to distinguish from normal fluctuations. That makes the initial screen useful. A rainfall surplus accompanied by a falling pond deserves investigation, although withdrawals, outlet flows, changing groundwater conditions, and measurement uncertainty still have to be considered.

Precipitation minus evaporation is one part of the full balance. It does not include all the water entering from the surrounding land, nor does it establish the exact amount leaking. A regional weather estimate also has limits when applied to a particular pond.

Use the weather record without dismissing the owner's experience

Owners are often closely attuned to how their ponds behave. A new pattern deserves attention. Natural Waterscapes compares that history with the climatic record rather than treating the owner's observation as something to disprove. Where needed, historical weather helps distinguish a recent structural change from an unusually dry interval or a supply change that has exposed an older seepage problem.

Natural Waterscapes’ water-balance tool provides precipitation and evaporation comparisons for the preceding 7, 14, and 30 days in the United States. Those periods are useful screening windows, not a required waiting period. Natural Waterscapes has used the comparison to help owners recognize circumstances in which weather and limited inflow could explain the decline, avoiding unnecessary effort on a sealing project.

For a pond with little contributing watershed, the surface precipitation and evaporation comparison can be especially informative, provided other flows are considered. For a pond with substantial contributing land, stopping there can miss an important part of the supply. Use the same dates for the weather, water-level, pumping, and runoff records. Seasonal operating decisions can require a longer record than the most recent month.

Include the watershed when the decision requires a refined balance

MyPond can support watershed delineation and runoff analysis, bringing the contributing land area and its soils into the assessment. A pond surrounded by highly infiltrative soils may receive less runoff from a rainfall event than an equally sized pond below a watershed that generates more runoff.

Natural Waterscapes uses MyPond to bring watershed area and soil information into runoff assessment. For water-balance work, the required result is a runoff volume over the period being evaluated. The NRCS curve number method estimates direct runoff depth from storm rainfall; multiplying depth by contributing area gives a volume. It is distinct from the Rational Method, whose basic equation estimates peak discharge using a runoff coefficient and rainfall intensity. A peak flow should not be substituted for a measured or modeled event volume. Use the method and assumptions documented for the analysis being reviewed. [2, 16]

Monthly precipitation helps explain seasonal water availability, but rainfall timing matters too. Several small storms and one intense storm can produce different runoff from the same total rainfall. Groundwater contributions require their own evidence; a humid climate does not guarantee dependable groundwater inflow.

Understand what the contributing land adds

Consider a one-acre pond receiving drainage from about 15 acres. Watershed soils in hydrologic groups C or D can generate more runoff than more infiltrative soils under otherwise comparable conditions. Cover, land use, antecedent wetness, storm characteristics, and routing still matter. Fifteen acres on a map is not a guarantee that a particular volume reaches the pond.

Mapped information can help characterize those influences, but the calculation remains an estimate. It should not be described as an exact measurement of the soil everywhere in the watershed or an exact measurement of inflow. Groundwater can add another contribution, and Natural Waterscapes does not treat an unmeasured groundwater inflow as established simply because the site appears favorable.

Measure changes over a consistent period

A useful record connects water level readings with rainfall, pumping, withdrawals, overflow, and operating changes. For a reservoir, relate level to a stage-storage curve so the analysis compares volumes rather than assuming a constant surface area.

As a geometry example, a one-inch change over a constant one-acre surface represents approximately 27,154 US gallons. That is a storage change, not automatically a leakage measurement. Sloping banks change surface area as the level moves, and the water balance determines how much of the observed change remains unexplained.

There is no single inches-per-day threshold that establishes a leak for every pond. The significance of a loss depends on local weather, water supply, basin geometry, intended use, and the reliability of the measurements.

Read the soil profile before selecting a treatment

The soil beneath the water body and the soil supplying its watershed perform different jobs. Basin and embankment materials control retention and structural behavior. Watershed soils influence how much rainfall becomes runoff. A useful site evaluation examines both.

Natural Waterscapes uses USDA NRCS soil information through MyPond and the pond leak evaluation tool to examine texture, soil horizons, hydraulic conductivity, and relevant suitability interpretations. These records help identify where further investigation is most valuable. [4]

Saturated hydraulic conductivity and its units

Saturated hydraulic conductivity, or Ksat, describes how readily water moves through saturated soil under a hydraulic gradient. It is expressed as a length per time, commonly micrometers per second, written μm/s, in the soil data discussed here. One μm/s equals 0.000001 meter per second. [5]

Natural Waterscapes places particular emphasis on Ksat when screening a pond that never held water despite a reasonable contributing watershed and precipitation supply. In that context, Natural Waterscapes uses the following ranges, expressed in micrometers per second, to guide the initial investigation:

Ksat rangeNatural Waterscapes’ initial assessment
Greater than 10 μm/sA strong concern for water retention in the circumstances described, prompting evaluation of remediation.
1 to 10 μm/sRequires closer consideration of rainfall, watershed contribution, inflow reliability, and the pond's intended operation.

These ranges guide Natural Waterscapes’ initial field assessment; they are not universal liner acceptance criteria. A value below either range does not certify that a pond or dam will perform adequately. The material, sampling location, soil condition, and source of the reported value must be understood.

Ksat is also not a direct prediction of how many inches the pond will fall each day. Seepage depends on the pressure difference driving flow, the length and area of the flow path, the arrangement of soil layers, and defects such as cracks or burrows. In the simplified Darcy relationship, flux equals hydraulic conductivity multiplied by hydraulic gradient. Translating that relationship into a site estimate requires a defensible representation of the actual flow system. [5]

Texture helps explain behavior but does not replace testing

Percent clay, silt, and sand helps characterize a soil and assess possible amendments. Texture must be read with the soil structure, condition, and profile. A single average clay percentage cannot show whether a connected sand layer, a root channel, or an inadequately compacted interface crosses the water-retaining zone.

Depth matters because excavation changes which horizons form the finished basin. A favorable surface soil may overlie a permeable layer. Materials moved during construction may be mixed, and soil placed in an embankment may behave differently from its undisturbed source.

Hydrologic soil groups and curve numbers describe runoff behavior relevant to water supply. An NRCS embankment suitability interpretation addresses a different question. These outputs should be used for their intended purposes rather than treated as interchangeable scores.

Verify mapped soil against the material on site

Natural Waterscapes compares observed soil characteristics with the NRCS descriptions. In Natural Waterscapes’ experience, many smaller pond embankments use material excavated on the property, sometimes from several parts of the basin. Imported fill is another possibility and should be established through construction records, observation, and testing where needed.

The map cannot establish what a contractor actually placed in a dam. Imported material should not be assumed superior merely because it came from elsewhere, and an acreage threshold cannot establish its origin. NRCS describes soil surveys as planning resources and notes that some engineering applications require onsite investigation. [6]

Where uncertainty affects the repair, representative test pits, borings, or other professional investigations can establish the profile and provide material for laboratory work. Natural Waterscapes favors particle-size analysis and saturated hydraulic conductivity testing, including the testing capability available within Natural Waterscapes. For an amended or reconstructed liner, the relevant question is how the proposed material performs in its intended compacted condition.

Scale testing to the consequences and uncertainty

Surface acreage is only one consideration. Suspected piping, the severity of damage, downstream exposure, and the contributing watershed can justify detailed investigation on a small pond.

Consider a one-acre pond receiving runoff from roughly 300 acres upstream. That configuration raises questions about the embankment, outlet, emergency spillway, and the inflow the system must manage. A 50-acre, well-supplied basin with only five acres of contributing watershed presents a different inflow problem. Its stored volume and downstream consequences still require attention.

Testing is valuable when it changes the design, establishes that an amendment can work, or prevents a major investment based on the wrong material assumption.

Treat karst indicators as a reason to investigate further

A sinkhole or evidence of soluble bedrock is a red flag for additional investigation, not an automatic rejection of the property. Natural Waterscapes’ approach is to examine the soil profile, depth and condition of bedrock, and potential water pathways with appropriate professional investigation. The same surface appearance can conceal very different conditions below.

In such settings, the design should limit leakage into susceptible underlying material and address stability as well as retention. A tight pond bottom may be an important part of that design, but it is not a substitute for understanding the foundation or a guarantee against karst processes. Test pits are useful where suitable; other investigation methods may be needed for conditions they cannot safely or adequately characterize.

Match the sealing method to the diagnosed problem

The choice between bentonite, a through-water treatment, imported soil, and a manufactured liner depends on the failure mechanism and the practical conditions of the project. Installed cost includes access, earthwork, material transport, dewatering where required, protection, testing, and restoration.

Repair approachConditions that support considerationMain decision requirement
Rework and compact existing soilSuitable material is present but construction quality is deficientDemonstrate performance at the intended moisture, density, and thickness
Soil amended with sodium bentoniteExisting material can form an effective amended linerSelect and test the material, mixture, and construction method
Imported suitable soilLocal material is inadequate and suitable borrow is availableVerify borrow quality and full delivered installation cost
Soilfloc through-water treatmentSoil seepage is a candidate for treatment while water remainsEstablish product suitability and distinguish seepage from structural defects
Geomembrane or geosynthetic clay linerA designed liner system suits the site and operating requirementsDesign subgrade, protection, joints, penetrations, and drainage
Local structural repair or reconstructionAn outlet, burrow, root channel, or damaged embankment creates a discrete problemEstablish the full defect and restore structural and seepage-control functions

Sodium bentonite and PondLock

Sodium bentonite swells when hydrated and can reduce permeability when incorporated into an appropriate soil sealing system. Natural Waterscapes frequently favors a high-swell sodium bentonite amendment where the site can be prepared, mixed, and compacted correctly. Natural Waterscapes uses PondLock for that approach. [8]

Product selection should consider the material's documented swell characteristics and its performance in the proposed soil mixture. A swell test helps characterize the bentonite; it does not by itself establish the finished liner's leakage rate or the correct application quantity for every soil.

NRCS Conservation Practice Standard 520 addresses compacted soil liners with or without amendments. The May 2016 national document specifies sodium bentonite with at least 22 milliliters free swell under ASTM D5890 unless other types are supported by laboratory testing for the design. The applicable state guidance and project requirements should be checked before specifying work. Compliance involves the liner design and installation, not just one product property. [9]

Application quantities need a stated basis. Pounds per square foot of treated area, percentage of dry soil mass, and quantities for a specified lift thickness describe different things. They cannot be substituted without accounting for the mixture and dimensions. Procurement should follow the actual treatment area and design, including side slopes where relevant.

Bentonite also needs to be placed where it can form the intended barrier. Adding material to a full pond and hoping it reaches a leak is a different operation from constructing a continuous, compacted amended-soil liner. Those approaches should not be sold as equivalent work.

Soilfloc and treatment while water remains in place

Soilfloc is a two-part polymer treatment offered by Natural Waterscapes for soil seepage and application through the water column. It provides an option to evaluate when draining a pond or reservoir would be difficult, expensive, or disruptive. The product information describes swelling within soil pores and interaction with fine particles as part of its sealing action. [10]

The appropriate application still depends on the leak mechanism and site conditions. A candidate assessment needs to address whether the problem is soil seepage, where treatment must reach, and what operating conditions could affect placement. A broken outlet joint or a dam undergoing internal erosion requires a repair decision that addresses the defect itself.

Owners should obtain current application instructions for the specified product and review water use, aquatic life, application conditions, and site access with the supplier and project professional. The expectation should be a defined treatment objective and monitoring plan, with a contingency if the required improvement is not achieved.

Imported clay and compacted soil liners

Importing suitable soil can be appropriate where local materials cannot meet the retention requirement. In Natural Waterscapes’ experience, hauling, placing, and compacting imported clay may be more expensive than some manufactured liner alternatives. The comparison changes with haul distance, material availability, basin dimensions, and the complete liner design.

The description "clay" is not a sufficient acceptance specification. Representative material needs to be evaluated in relation to the intended construction, including its compatibility with the underlying soil. The repair must provide continuity across the area to be sealed and around connections that could bypass it.

Geomembranes and geosynthetic clay liners

A manufactured liner can be a strong candidate when the proposed soil treatment cannot meet the objective or when the owner prefers a liner system. It must be evaluated as an installed assembly, including its subgrade, seams, anchors, penetrations, protective layers, and any required drainage or venting. NRCS Standard 521 addresses these systems and the need to follow the selected material's installation requirements. [11]

Natural Waterscapes’ approach can include nonwoven geotextile below a geomembrane, the liner itself, protective fabric above, and a sand cover where the desired fishery and habitat call for it. That is a project approach rather than a universal requirement for every liner. The protective layers and cover must suit the material, slopes, loading, and use.

Large installations may require field seams. The appropriate response is a defined seaming and quality-control plan, together with careful treatment of penetrations and protection against damage. Seams do not make failure inevitable, but their workmanship is part of the system's performance.

A geosynthetic clay liner is another distinct option: a manufactured bentonite-containing barrier. It should not be confused with a loose bentonite application or an ordinary geotextile cushion. Material compatibility and the required cover or confinement belong in its design. [11]

Other amendments require their own technical basis

Chemical dispersants and proprietary liquid sealing systems are additional product categories. They have different soil requirements and application methods. NRCS recognizes dispersant treatment for appropriate soils, but a dispersant is not interchangeable with bentonite or a polymer sealant. [9]

An owner evaluating an alternative should ask for the specific mechanism, suitable and unsuitable soil conditions, required preparation, compatibility with the intended water use, and the evidence supporting the proposed result. A comparison based only on product price leaves out much of the work that determines success.

Design localized embankment repairs around the full defect

A root channel or animal burrow may create a concentrated pathway through otherwise suitable soil. Natural Waterscapes may excavate and rebuild an affected zone with compacted soil amended with sodium bentonite where site conditions support that repair.

The extent must be established from the soil, damage, flow path, and material encountered during excavation. A visible opening may reveal only part of the affected area. The repair needs to connect with suitable material around and below the defect while maintaining safe excavation conditions and embankment stability.

The visible opening does not determine the excavation limits. In a field example, a six-inch burrow illustrated a repair that could extend roughly 12 feet to either side and four feet below the defect where feasible. That is an example of the possible scale of a repair, not an NRCS sizing criterion, a universal ratio, or a homeowner excavation instruction. Soil conditions, the full flow path, structural stability, and the repair design establish the actual limits.

Temporary stabilization is a separate decision. Natural Waterscapes may consider sandbags and a chipped bentonite product called Hole Plug as possible measures for a known upstream entry. Their use does not establish that internal erosion has stopped or that the structure has regained its original strength. Permanent work requires investigation and a repair design.

An incoming storm or substantial stream inflow can change the urgency and available options. Pumping or a stabilized siphon are measures professionals may consider in an emergency plan. Capacity, expected inflow, safe discharge, and the dam's response to lowering all matter; "lower it as fast as possible" is not a general operating instruction.

Connect seepage reduction with water quality

Water quantity and water quality are connected decisions. A limestone spring supplying abundant, high-quality water can sustain a pond even where the bottom has appreciable conductivity. In that situation, the owner may reasonably accept the seepage. If the replacement water carries an undesirable nutrient or sediment load, retaining more of the existing water can reduce the amount of that replacement supply needed.

The practical objective may therefore be twofold: tighten the pond bottom and reduce the inflow that creates a water-quality burden, while retaining enough supply for the intended operating level. Natural Waterscapes does not recommend diverting water merely because it is runoff. Natural Waterscapes compares the actual sources, the pond's needs, and the consequences of changing them.

Persistent algae blooms can prompt investigation of phosphorus inputs, but the bloom itself does not identify the source. Watershed land use helps direct that investigation. Water testing is needed to characterize the incoming water, and conditions within the pond can also sustain nutrient availability. A useful assessment connects the source, its concentration, the volume entering, and the timing of delivery.

Sediment has a separate cost. An unstable watershed can repeatedly deliver material that settles in the pond, reduces depth, and creates future maintenance work. Controlling seepage does not eliminate that sediment source. Watershed stability and inlet management belong in the plan when they affect the pond's long-term usefulness.

Test well water rather than assuming it is the clean alternative

For ponds supplied by both watershed runoff and a well, Natural Waterscapes often tests storm-condition surface inflow and the well discharge separately. Natural Waterscapes has encountered wells with substantial phosphorus concentrations, despite the owner's reasonable expectation that groundwater would provide clean replacement water. Elevated mineral content can also affect suitability; the relevant constituents and intended water use determine what needs evaluation.

In some projects, the surface source had elevated phosphorus but the well contained more. Natural Waterscapes has installed pump intakes in an adjacent stream to use the more suitable available source and then treated the remaining phosphorus burden. That field example illustrates source selection based on evidence; it is not a general instruction to divert a stream or assume every stream is preferable to a well.

If the well is the better source, it may carry more of the supply requirement. If the surface inflow is high quality and reliable, Natural Waterscapes may favor that source and reduce well operation. Source concentration alone is not the whole comparison: the volume delivered, seasonal reliability, pumping cost, and any treatment requirements also matter.

Control replacement water according to need

Many pond wells run on timers. A timer determines how long water is pumped, but it does not establish whether the pond needs that water at the time. Where appropriate, a float or water-level sensor can limit pumping to periods when the pond falls below a selected level. The operating range should reflect the pond's intended use and the source's ability to keep up.

Where source-water treatment is justified, a metered dosing or filtration system may be considered. The choice depends on the contaminant, source testing, flow, water use, and operation. Dosing at an inlet does not by itself establish that phosphorus has been removed from the system; the design must address the treatment mechanism and the handling of any resulting solids or residuals.

Reducing seepage can therefore affect more than the number on a water-level gauge. It may reduce pumping hours, the mass of nutrients introduced with replacement water, and the quantity of treatment required. Those benefits should be evaluated from actual operation rather than promised as a fixed outcome.

Design inflow controls around useful water

Persistent outflow is a useful starting observation when evaluating whether all incoming water is needed. It can indicate an opportunity to manage the supply, but surplus during a wet period does not establish surplus during a dry period. Natural Waterscapes returns to the water balance and examine representative water-stressed periods, including sustained dry intervals, before deciding how much inflow to retain.

Where water approaches through a defined channel, the site may offer a practical point of control. A designed inlet basin with staged openings or a suitable weir arrangement can admit useful low flows while diverting part of the stormflow. The arrangement depends on channel levels, flow range, bypass capacity, sediment, and the receiving pond. Descriptions such as an inverted or reverse V-notch weir require an actual hydraulic detail before they become construction instructions.

The design does not create water. If base flow dries up, the pond still needs sufficient stored water, another suitable source, or an accepted decline in level. Use the dry-period balance to test that condition, and separately design safe passage for stormwater. Water-supply planning and flood conveyance answer different questions.

Automated controls, potentially including solar-powered gate actuation, are a future direction worth evaluating. They should not be presented as an existing feature of every installation. Source-water quality, sensor reliability, power, failure position, and maintenance would all influence whether automation improves a particular site.

Keep maintenance visible

Inlet controls can be out of sight and out of mind because forebays and intake structures are often away from the pond's high-use areas. Sediment buildup, gate failure, and clogged orifices or weir openings can change the supply before the owner notices. A design that performs only when clean needs an accessible and realistic inspection and cleanout plan.

Identify who will inspect the inlet, what normal operation looks like, and how to record a change. Maintenance should be considered when selecting the structure and locating access, not added after construction. A drop in admitted flow may reflect a blockage rather than a change in watershed hydrology.

Consider access and water use before selecting the work

Whether the pond must stay filled can change the practical options, but it does not establish the cause of the leak. Record fish and other uses, equipment access, shoreline conditions, water sources, and whether drawdown is feasible. A through-water option still needs a suitability check; an earthwork option needs workable material and an installation plan.

Compare the delivered materials and the work needed to install them, not just the price of a package. Include hauling, mobilization, preparation, drawdown or replacement water, protection, monitoring, and restoration. Where a well has been masking the loss, include its pumping and treatment burden in the comparison.

Verify performance after the repair

Define success before work begins. For one pond, success may be maintaining the intended operating range without frequent well additions. For another, it may be a measurable reduction in unexplained loss at comparable water levels. A reservoir may require both an operating improvement and continued confirmation of dam safety.

Retain the original observations and construction records. Document the area treated, material and quantity used, installation conditions, relevant soil or compaction tests, and any changes to outlets or operating practices. Repeat water level and flow observations after treatment.

A slower decline after repair can be encouraging, but rainfall, cooler weather, reduced withdrawals, and a lower water level can also change the result. Compare periods with the water balance in view and continue observation long enough to test the intended operating conditions.

Keep retention performance and structural performance distinct. Less water loss does not prove that an internally eroded embankment has been restored. Conversely, a properly functioning drain may continue to discharge while controlling seepage safely. [3]

Return to the same balance after the work

Natural Waterscapes’ post-treatment review returns to the weather and supply analysis used at the start. The most recent 30-day precipitation and evaporation comparison can help explain the operating period. Where the watershed contribution is significant, bring in the runoff estimate using the soils, land cover, rainfall, and assumptions documented in that analysis.

Compare equivalent periods and identify changes in pumping or outflow. If the pond rises into a wider part of the basin, the same depth change represents a different storage volume. If it falls, the reduced hydraulic head can change seepage. These effects matter when claiming a measured reduction rather than simply reporting that the owner is pleased with the level.

A useful result can be less frequent pumping, a more reliable operating range, or a demonstrable reduction in losses. State the observed outcome and the limits of the evidence. Do not convert a successful field example into a promised performance percentage for a different pond.

Begin with the soils and water balance of your water body

Water has value even when its loss never appears as a separate line on a bill. Repeated pumping, an unreliable operating level, and the time spent compensating for seepage can accumulate for years. Understanding those losses makes it possible to evaluate a repair on its actual usefulness.

Use the pond soil and leak evaluation to examine the mapped soils beneath your pond and organize the initial leak assessment. Use MyPond to bring the pond, watershed, and water balance into a continuing management record. Both provide a starting point for the site-specific investigation.

For an existing pond, assemble its construction history, recent water level observations, inflow and withdrawal information, and photographs of suspect areas. For a new pond, investigate the soils and water supply before committing to the excavation plan. Reservoir operators can begin with the operating record and known seepage monitoring locations.

That information supports a recommendation grounded in the actual water body: what can be retained, which repair fits the problem, how the work should be executed, and how its performance will be judged.

Soil characteristics matter.

Choose the next step that suits you

Use the optional homeowner guide to record pond history, approximate loss, supplemental water, and any soil description or analysis-report link. Skip unknown items and continue. The guide works on paper or as a fillable PDF; it does not submit information automatically.

You can explore through-water treatment, suitable native-soil compaction, bentonite amendment, a liner, or repair of a specific feature. Those are approaches to evaluate, not automatic prescriptions from a checkbox. Natural Waterscapes’ team remains available even if the observations appear clear and you simply prefer personal guidance.

Companion guide and ways to get help

Download the companion Homeowner Pond Leak Guide. It supplements the explanation in this article and can be used without completing every field. You can use self-service resources or contact Natural Waterscapes’ team at any stage.

Explore the pond soil and leak evaluation

Talk with Natural Waterscapes’ team about your pond

Use MyPond

Sources and technical references

Field examples and recommendations attributed to Natural Waterscapes’ experience come from the Natural Waterscapes technical interview. Product pages are supplier information, not independent comparative trials. NRCS documents are identified by edition; consult applicable state and project requirements. Historical source prices are not used.

1. USGS Water Budget Science in Oklahoma and Texas

2. TxDOT NRCS Curve Number Loss Model

3. ASDSO Seepage Through Earthen Dams

4. Natural Waterscapes soil analysis and MyPond

5. NRCS Soil Survey Manual Chapter 3

6. NRCS Web Soil Survey

8. PondLock supplier information

9. NRCS Standard 520 May 2016 national edition

10. Soilfloc supplier information and application guidance

11. NRCS Standard 521 August 2023R

16. TxDOT Procedure for using the Rational Method

Download and use the companion guide

Download the PDF guide

Directions, individual tasks, and room for observations. Use digitally or print. Nothing submits automatically.

Start with what you know

TLDR

Begin with your pond's history and an estimate of its water loss. Note any water you add to keep it full. Soil information and water-level tracking are optional. Explore repair approaches or talk with our team at any point. You do not need to complete this guide before asking for help.

1. Describe the pond

Space to record: Pond name or location

Space to record: Approximate surface area and units, if known; otherwise write Not sure

Has the pond ever stayed at the water level you wanted? Mark one.

  • Yes
  • No
  • Not sure

Space to record: If yes, approximately when did it begin dropping below that level?

Space to record: When do you notice the drop? All year, dry weather, other, or Not sure

Space to record: What would you like to improve about your pond?

You may skip any question you cannot answer. Staff help and self-service are both available using the links at the bottom of every page.

Estimate the water loss

2. Record your best estimate

An estimate is fine. You do not need to begin a measurement program before moving forward.

Space to record: Approximate water-level drop in inches; or write Not sure

Space to record: Over what interval? Per day, per week, or describe another interval

3. Note any water you add

Are you adding water to help maintain the level? Mark one.

  • Yes - answer the optional questions below
  • No - skip to the next page
  • Not sure

Space to record: Where does the added water come from? Well, stream, other, or Not sure

Space to record: About how often or how long does the pump run? An estimate is fine

Space to record: Does the estimated drop occur with the pump on, off, or Not sure?

Space to record: Other known inflow or outflow observations, if any

A steady level can still require substantial replacement water. These observations give context; they do not by themselves measure seepage.

Add soil information or readings

4. Add soil information if you have it

If you know your soil type, record it below. Otherwise write Not sure. You can optionally use the leak tool, locate and outline your pond, follow its analysis steps, and paste a link to your completed report. You do not need to select a conductivity value or compare soil layers.

Space to record: Soil type or description, if known

Space to record: Completed analysis report URL, if available

5. Track water level only if useful to you

Choose a fixed, non-floating dock reference or a securely installed staff gauge. From a fixed dock, mark one safely accessible point and measure vertically down to the water. A larger distance means lower water. For a staff gauge, read the scale at the water surface. Keep the same reference and units.

About once a week is a useful starting interval, or choose an interval that works for you. Record the date and measurement. There is no required monitoring period before requesting help.

  • I chose a measurement method, if I want to track the level
  • I identified a fixed reference point
  • I recorded a first reading below

Space to record: Method / reference / units / preferred interval

Space to record: Reading 1: date, time, and measurement

Space to record: Reading 2: date, time, and measurement

Space to record: Reading 3: date, time, and measurement

Explore repair approaches

Use these options as a reference, not a diagnosis or product prescription. Mark any approach you would like to explore and write questions beside it. You can ask our team for help even when your observations seem clear.

6. Consider whether water must stay in place

Mark one.

  • The pond needs to stay filled
  • I could consider lowering or draining it
  • I would like advice

Treatment with water in place

A through-water treatment such as Soilfloc may fit suitable soil-seepage conditions. Review suitability and application requirements before choosing it.

  • I would like to explore treatment with water in place

Space to record: Notes or questions about through-water treatment

Preparation and compaction of existing soil

If the treatment area can be exposed, suitable native soil may be prepared and compacted. Establish that the material can meet the intended retention requirement.

  • I would like to explore using and compacting the existing soil

Space to record: Notes or questions about existing-soil compaction

Compare the remaining options

Bentonite soil amendment

A bentonite amendment such as PondLock may fit where soil can be prepared, mixed, and compacted appropriately. Rate and installation requirements depend on the site and material.

  • I would like to explore a bentonite amendment

Space to record: Notes or questions about bentonite

A liner system

Compare site preparation, installation requirements, and the complete installed cost.

  • I would like to explore a liner system

Space to record: Notes or questions about a liner

A specific pipe, outlet, or embankment feature

If you have noticed a problem with a particular feature, record what you saw and where. A pond-bottom treatment may not address it.

  • I have a specific feature I would like evaluated

Space to record: Feature, location, observation, or photograph reference

Continue in the way that suits you

Explore treatment information yourself, talk with our team, or do both. Bring whatever you already have. Estimates and unanswered questions are welcome. No completed worksheet or selected treatment is required.

Self-service pond soil and leak evaluation

Speak with Natural Waterscapes: 877-493-7660