Pool Water Conservation and Leak Checks

Applies to: In-ground and above-ground pools with sand, cartridge or DE filters, with or without automatic fill valves. Local water rules vary, so check with your water utility or city.

Where pool water goes

EPA WaterSense says pools lose water through evaporation, pool cleaning, leaks and splashing. It calls evaporation one of the leading causes, especially in hot, drier climates, and says the rate depends on temperature, humidity and wind speed.^[1][4]

Cut evaporation

• Use a cover. EPA WaterSense says covers can be used on in-ground and above-ground pools and can prevent up to 95 percent of evaporation. They only work when they are on the pool.^[1][4]
• Block the wind and add shade. EPA WaterSense says a windbreak and shade from landscaping can both reduce evaporation.^[4]
• Keep it cooler. Maryland's Department of the Environment says lowering pool temperature reduces evaporation, especially when the pool isn't in use.^[2]
• Turn off water features when no one is swimming. EPA WaterSense notes they increase evaporation and water lost to wind and splashing.^[4]
• Lower the water level to reduce splash-out, per Maryland's Department of the Environment, but not below what your skimmer and manual call for. UF/IFAS Extension warns that a pool drained below the skimmer could burn up the pump motor.^[2][5]

Backwashing and filter choices

Maryland's Department of the Environment says to backwash only when necessary and to keep the pool and filter clean so you backwash less often. EPA WaterSense agrees: skimming and vacuuming leaves and debris reduces the load on filters, and a pressure gauge can help you tell when a backwash is due.^[2][4]

• Sand filters: EPA WaterSense calls them the most common type for residential pools.^[4]
• Cartridge filters: EPA WaterSense calls them the most water-efficient because they do not need backwashing.^[4]
• Above-ground sand filter pumps: Bestway notes that backwash and rinse cycles lower the pool's water level.^[7]

Follow your own filter's manual for when and how to backwash or clean it.

Where backwash and drain water can go

Rules differ by place. Maryland's Department of the Environment suggests running backwash onto lawns and shrubs and keeping runoff on your property, and says that if acid has been used to clean the pool, the water should be neutralized. EPA WaterSense says backwash water used on a lawn or garden should not be freshly chlorinated, so it is safe for plants. Southern Nevada counts failing to send pool drainage to the sanitary sewer, when available, as water waste. EPA WaterSense says to check local regulations before draining pool water into sewers or onto your property.^[2][4][8]

Check for leaks

EPA WaterSense says leaks can occur in the liner, pump seal, piping, pool-to-pipe connections, pool edges and pipe joints. Wet spots around the pool or air bubbles in the return line or pump strainer can be signs of a leak, and small leaks can quickly become big ones.^[4]

The Southern Nevada Water Authority calls the bucket test one of the easiest ways to check:^[3]

1. Turn off the automatic fill valve.^[3]
2. Set a bucket on a pool step so its rim sits a few inches above the water line.^[3]
3. Put a heavy weight in the bucket and fill it until the water inside matches the pool level.^[3]
4. Leave it undisturbed for several days, then compare the two levels.^[3]
5. If the bucket level is noticeably higher than the pool level, you may have a leak.^[3]

• EPA WaterSense notes that automatic fill valves can malfunction, and that filling by hand helps you notice weekly water loss.^[4]
• Above-ground pools: Bestway says to check the gasket when a hose connection leaks, and that small liner holes can be patched without draining.^[7]

Local water rules and help

Check your local water-waste rules. In Southern Nevada, for example, city and county ordinances and water provider rules prohibit water waste, and fees can apply. EPA WaterSense notes that some utilities offer rebates on qualified pool covers, so check with your water utility.^[4][8]