Cover a pool between swims
Why this can help
A suitable fitted cover can reduce evaporation while the pool is covered. Use a cover already available and compare water loss over the same covered intervals.
One possible next step
Check the existing cover’s instructions and fit it after everyone leaves the pool, keeping required access protection in place.
What changes the outcome
Retained evaporation water is not guaranteed tap-water saving: rain, overflow and other losses matter. A solar or bubble cover is not a safety cover. Preserve required access protection, follow product instructions and remove the cover fully before swimming.
Your illustrative scenario
Over one year · with the assumptions below
You
5,184 litres of water evaporated less
You + 10 friends
57,024 litres of water evaporated less
1,000 participants
5,184,000 litres of water evaporated less
These are scenarios, not measured personal or collective savings. One separate household per participant. People sharing a home count it once, not once each.
Your inputs
- Pool water surface
- 32 m²
- Evaporation per interval without cover
- 2 mm
- Evaporation per same interval with cover
- 0.2 mm
- Covered intervals per year
- 90
Calculation of the difference: 32 m² × (2 − 0.2) mm × 90 = 5,184 litres of water evaporated
Calculation boundaries
Water retained by reducing evaporation during the specified intervals, not guaranteed tap-water savings. Use the same interval and weather for both inputs: a night is not a full day. Excludes rainfall, overflow, leaks, heating energy and cover manufacture.
32 m², 2 mm without a cover, 0.2 mm with a cover and 90 intervals are illustrative, not local measurements. The example implies a 90% reduction during those intervals; no universal reduction is assumed. Replace both depths with appropriate local evidence.
Sources and calculation references
- Pool Water EfficiencyU.S. Environmental Protection Agency, WaterSense · 2026
- Jump Into Pool Water Efficiency, EPA-832-F-22-015U.S. Environmental Protection Agency, WaterSense · 2022
Read the method: universalizable.com/en/method/ · One sheet · print double-sided, long-edge binding