What is Pool Water Evaporation?


Around this time of year, it's common for pool owners to worry about their pool losing water. Is it pool water evaporation? Is it a leak? Or maybe it was because of the excessive splashing from the pool party the day before. To help you determine if your pool is losing water because of a leak or due to pool water evaporation, let's quickly cover what pool water evaporation is:

What is Pool Water Evaporation?

Pool water evaporation refers to the amount of water that your pool will naturally lose because of the sun and other environmental factors. How much pool water evaporation you can expect will depend on:

  • Your pool's surface area:

  • The temperature outside

  • Relative humidity

  • Wind

Generally speaking, a loss of 1/4" to 1" of lost water a day would likely be due to pool water evaporation, depending on the time of year, and anything beyond that may indicate a leak or be the result of "splash-out" water.

How to Find a Leak in a Pool

If you think you have a leak, test it by performing a bucket test. Take a bucket and set it on the steps of your pool (weigh it down with rocks or bricks if necessary). Fill it so that the water in the bucket is level with that of the pool, and leave it for 24 hours. You'll then be able to see how much water has been lost.

If your pool is losing a significant amount of water, start by checking the obvious areas where leaks can happen. Look at:

  • The filter

  • The pump

  • The heater

  • Pipe valves

  • The ground (are there any wet areas around the pool? Are there any eroding or sunken areas?)

If you have a vinyl liner, look closely for any tears or liner separations around any fittings, returns, skimmers, lights, cleaner lines, steps and corners. If you turn off your filter, a dye or food coloring can be used to try to further pinpoint any cracks (the dye will be sucked into and highlight the crack).