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Common Causes of Pool Evaporation

Common Causes of Pool Evaporation

3rd May 2021

Each day, your pool will lose about a quarter inch of water, depending on weather and geographical factors. For example, changes in humidity, sunlight, and wind determine how much and how quickly water evaporates. Let's look at some of the most common causes of pool evaporation, so that you can adjust accordingly and keep your water level right where it should be. Though evaporation is avoidable, knowing the causes of it can help you react quickly in order to avoid having to spend a lot of time filling it before swimming.

In-ground Swimming Pool With Poolside Tile


Humidity is a main cause of water evaporation. Particularly, a lack of humidity is the biggest culprit. The drier the heat is, the more water disappears. Locations with higher humidity lose less water. If you have a string of days with low-humidity, try fillig the pool each day for about two hours. This will replace the water it loses each day, as opposed to losing a significant level of water over the course of a week.

Exposure to Sunlight & Wind

If you know there will be a few days you cant use the pool, keep it covered. Exposure to the elements is another huge factor in evaporation. The longer your pool is exposed, the quicker you'll lose water. It's good to keep your pool covered whenever it's not in use for this very reason. Keeping it covered will also keep the water warm and clear from debris, so there are a lot of benefits that make it worth the extra effort.


The hotter it is outside, the more water you'll lose. This one is obvious to most people, but they don't always think about it. On extremely hot days, make sure you fill up when everyone's done swimming. In addition to losing water from heat, you'll also lose water from splashing and swimming. On hotter days, you'll likely have more people swimming, and swimming for longer. So, in addition to the lose from swimmers, you'll also have loss from the heat. When everyone is finished with the pool, fill the water until it's a little above your normal line. Just like with humidity, you'll want to fill it every day if you have a string of intense heat for several days.