Pool, Spa & Water Treatment Chemistry worked example
Evaporation Water Loss with water surface area of 1,300 ft2: a worked example
Push water surface area up to 1,300 ft2 and the picture changes. This example computes every intermediate figure at that operating point. Use it to separate normal evaporation from possible leaks or to plan make-up water.
The inputs for this scenario
- Water surface area: 1,300 ft2 (raised for this scenario; the documented default is 512)
- Daily evaporation depth: 0.25 in / day (unchanged)
- Gallons per square foot-inch: 0.62 gal / ft2-in (unchanged)
- Exposure adjustment factor: 1 x (unchanged)
Working through the calculation
- Applying the documented formula (Evaporation loss = surface area x evaporation depth x 0.623 x exposure adjustment) to the inputs above produces each figure below.
- At this operating point the engine returns 202 gal / day for evaporation water loss, the number this scenario is built around.
- At this operating point the engine returns 202 value for base product.
- At this operating point the engine returns 1 x for multiplier.
- At this operating point the engine returns 325 value for factor a x b.
How this compares with the baseline
- Against the tool's baseline example, where water surface area sits at 512 ft2 and the headline result is 79.74 gal / day, this scenario comes in 154% above the baseline at 202 gal / day.
- It computes the gallons per day lost to surface evaporation from a pool's water surface, adjusted for cover, wind, and humidity. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.
Results at a glance
- Evaporation water loss: 202 gal / day (headline result)
- Base product: 202 value
- Multiplier: 1 x
- Factor A x B: 325 value
Run it with your numbers
- Every input above is editable in the live Evaporation Water Loss calculator, which recalculates instantly and can be shared with the inputs intact.
Last reviewed 2026-05-12.