You can do the “bucket test” on your pool to measure evaporation. Place a bucket of water beside the pool and mark both the water in the bucket and the pool water level. Wait 24 hours then check the loss of both. If the pool loses more water than the bucket, then you have a leak.
If the water went down a similar amount in the pool as well as the bucket, then you lost water due to evaporation. If it went down more in the skimmer and not much at all in the bucket then you have a pool leaking.
An easy way to determine if you have a pool leak or evaporation issues is to do a bucket test. Simply fill a 5 gallon bucket about 3 inches from the top of the bucket and place it next to the pool. With electrical tape or another easily removable tape mark the water line on the pool and the bucket.
Evaporation occurs whenever you expose wind or air to the surface of your pool. So in short, this applies to every pool, all the time. Water molecules rise to the surface, form into a vapor and eventually get released into the air. Heated pools on cool nights experience evaporation more rapidly.
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.
This will vary depending upon several factors including: weather, if the pool is covered or not, bather load, and if it is heated or not. With pools that are covered, a good rule of thumb is that they should not have to be refilled more often than once every 2 weeks.
Typically, pools lose water for one of two reasons: Evaporation or a leak. Evaporation naturally occurs in any body of water, but it may increase under certain conditions, such as hot, humid weather. Leaks, however, indicate a bigger problem that a professional may need to address.
Most pool leaks are not in the underground plumbing, although it's every pool owner's worst fear, a large backhoe coming in and ripping up the pool deck. It does happen occasionally, that a leak occurs at a pipe connector under the pool deck, or beneath the skimmer, but repair rarely involves a backhoe.
Quick answer: You can expect to lose between 2 mm to 2 inches of water in your pool per week due to evaporation, depending on the various factors we'll get into in this article.
Losing a half-inch or more overnight indicates a problem. A covered pool or spa tub will lose very little water from evaporation in a 24-hour period. Check the water level in your pool or spa tub before you cover it and turn off the pump system. You will know if the water level drops below normal.
Pool Is Losing Water When the Pump Is Off
If you've turned off your pump system for a day and the pool level is dropping more than 1/4–1/2” per day, you might have a pool leak. The leak is likely somewhere in the structure of the pool or on the suction side of the pool pumping system.
RECOMMENDATIONS TO MINIMIZE WATER LOSS
The number-one way to combat evaporation is with a pool cover. It's estimated that a pool cover will reduce evaporation by 95 percent. Solar covers can heat your pool in the off-season, too. A pool cover reduces the pool's chemical consumption and reduces your cleaning time.
Most pools experience between 3mm - 7mm of water loss each day, depending on where you live.
An uncovered pool will lose water in the winter to evaporation in the same way it does during the summer. But the water loss is only about a quarter-inch on average during a 24-hour period when the pool is not in use. An uncovered or covered pool can have problems in the plumbing lines or pump.
The average pool water evaporation rate is about a quarter of an inch of water per day or more than two inches in a week, which on a 33′ x 18′ swimming pool (an average pool size) is more than 2500 liters or approximately 600 gallons a week; this may vary depending on your climate and the factors listed above.
Use swimming pool covers to reduce evaporation!
They can dramatically slow down evaporation, particularly on hot days and cold nights. Studies confirm that covering a pool can reduce evaporation by up to 95%! That's big water savings! A swimming pool cover traps the vapors and the heat from escaping.
Another reason for a pool to lose water over the winter is due to the harsh elements. Ice, snow, and water can accumulate on top of the pool cover. When too much weight forces the pool cover into the surface of the pool, water may rise up and over the pool sides. This is called displacement.
Your pool also loses water in summer, up to 2 inches per week, due to the heat of the air. You can employ a swimming pool cover to protect the pool from these powerful rays. A pool cover will also keep heat in your pool when the weather is cold. In summer, the air around the pool is hotter than the pool water.