How much water evaporates from a pool each day?

Pool water evaporation rates in one day or one week

It can be easy to misdiagnose pool water evaporation. Evaporation rates depend on both geographic and environmental factors. Pool owners who notice a sizeable water loss in their pool should implement the Bucket Test to determine whether their pool has a leak or is just experiencing routine water evaporation. If pool owners or maintenance workers are constantly filling up the pool, there may be a leak.

On average, swimming pools lose about a quarter of an inch of water each day, yet variations in wind intensity, humidity and sunlight can drastically change water loss rates.

Some of the strongest and most intense wind in the country can be found in mountainous regions. The wind will undoubtedly have an effect on pool water, as wind can blow water particles and cause speedy evaporation. Other windy regions include the Great Plains, the Great Lakes and most coastal locations.

If wind is not the problem, a lack of humidity may be. The central continental United States is known for its dryness, while the East and West coasts, the Great Lakes, Florida and northern Idaho are known for more humid climates. Humidity refers to the amount of moisture in the air- when air is moist, water molecules tend to stay in place, rather than infiltrating the already water-laden air. As a result, humid air keeps water in the pool, while dry air allows pool water to evaporate.

Non-humid areas also tend to be sunlight-intensive, providing another reason for pool water loss. When the sun's rays beat down most strongly, water molecules evaporate and dry up, converting to air molecules - a perfect match for the area's non-humid air! As a result, people in sunny, non-humid areas, especially the southwestern United States, can experience more pool water evaporation.