Pond Water Balance Map
See whether ponds and open water in your area are gaining or losing water — updated for the contiguous United States.
Net Water Balance — Open Water
Every pond is constantly gaining water (mainly from rain and runoff) and losing it (mainly to evaporation, along with seepage and outflow). Its water balance is simply the net of those two — whether it's coming out ahead or falling behind. When losses run ahead of gains for weeks at a time, the water level drops, banks and structures get exposed, and dissolved nutrients concentrate in a shrinking volume. This map shades the recent balance across the country so you can see, at a glance, whether the broad conditions in your region have been adding water to open ponds or drawing it down.
How to Read the Map
Each shaded area shows the recent net water balance for open water in that part of the country, accumulated over the trailing window you select (7, 14, or 30 days). The scale is diverging:
Blue tones mean open water has been gaining more than it lost over the window — a net surplus. Warm tones (yellow, orange, red) mean the opposite: losses have outpaced gains, and open ponds in that area have been trending down. Neutral shades near the middle of the scale indicate the two roughly cancel out.
Use the window buttons above the map to switch between the last 7, 14, and 30 days. A shorter window reacts quickly to a recent dry spell or a big storm; a longer window smooths those out and shows the sustained trend. Click or tap any area to see the balance range for that spot, and toggle Show detailed shading for a finer-grained view.
The values shown are a modeled regional estimate for general guidance across large areas. They describe broad conditions for open water — not the exact behavior of any one pond, which also depends on its depth, soil, shade, inflows, and whether it holds water well. Treat the map as an early-warning signal, not a substitute for checking your own water-level gauge.
Why Water Balance Matters for Your Pond
A prolonged stretch of net loss is one of the first signs of trouble that pond owners can actually act on. As the level falls, several things happen at once. The pond holds less water, so the same amount of nutrients, salts, and any treatments become more concentrated. Shallow shelves and shorelines dry out, stressing habitat and inviting weeds along the newly exposed margins. And a smaller, shallower pond heats up and loses oxygen faster, compounding other stresses on fish.
Persistent loss also helps you separate weather from a leak. If the map shows your whole region in strong net loss, a dropping level is likely the season doing its work. But if your pond keeps falling while the surrounding area sits near neutral or in surplus, that points toward seepage — and a pond that won't hold water is a fixable problem.
When a pond drops faster than the weather explains, sealing the leak is the fix. Bentonite, SoilFloc, and liner options for ponds of every size.
What to Do When the Map Shows Net Loss
Confirm it on the ground. Mark your current water level with a stake or a fixed reference and check it over a week or two. Comparing your real drop against the regional trend on this map is the quickest way to tell normal seasonal loss from a leak.
Protect fish and water quality. A shrinking pond concentrates nutrients and loses oxygen faster, which raises the odds of algae blooms and low-oxygen events. Keeping aeration running through a drawdown helps hold dissolved oxygen steady and keeps the water mixed.
Fix a genuine leak. If your pond is losing water well beyond what the regional balance explains, it's seeping. Depending on the soil and the situation, that's addressed with a bentonite or polymer sealant or a liner — see our guide to sealing a leaking pond to choose the right approach.
Plan top-ups and treatments around it. If you dose treatments by volume, remember that a lower level means a smaller pond — recheck your dimensions so you don't over-apply.
Coverage & Updates
The map covers open water across the 48 contiguous states and updates daily, so the balance you see reflects recent conditions. If the map hasn't loaded yet, the latest update may still be publishing — it will appear automatically once it's ready. This tool is a free resource from Natural Waterscapes and is intended for general guidance; for a decision about your specific pond, talk to one of our experts.
Pond dropping faster than it should?
Talk to one of our pond experts about sealing a leak, holding your water level, or protecting fish through a drawdown.