Heated pools do result in more evaporation, so more make-up water is required to refill heated pools than unheated pools. Whether using solar heating, heat pumps, or gas heaters, heated pools do require more water.
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. This is also why heated pools lose most of their heat overnight.
Depending on various environmental factors—including your location, average daily temperature, and the amount of sun your pool gets every day—your pool may lose more than half a centimeter of water every day. This translates to just under five centimeters a week, on average.
For example, high temperatures, lots of humidity, and high winds can increase your pool's evaporation rate. Pools without enclosures or tree cover will also evaporate faster than those with shade and protection because they are more exposed to the weather elements.
Pool Loses Water Overnight
If you use a heater, your pool warms up and evaporates more water. As the summer air stays warm overnight, your pool will evaporate even faster. Keeping your pool covered can help keep water and heat from escaping into the air.
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.
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 your pool lost water overnight and it is more than the quarter-inch due to evaporation, you probably have a leak. Evaporation accounts for a minor amount of water lost each day. Losing a half-inch or more overnight indicates a problem.
The differential that occurs between the pool water temperature and the air temperature on late summer nights causes water to evaporate at an accelerated rate. In some cases you might see a water level difference of 1-3 inches overnight. Depending on the size of your pool, that can be over 500 gallons of water loss!
Heated pools do result in more evaporation, so more make-up water is required to refill heated pools than unheated pools. Whether using solar heating, heat pumps, or gas heaters, heated pools do require more water.
Re: Evaporation of Chlorinated versus Non Chlorinated water
Correct me if I'm wrong - but, you hypothesized that chlorinated water would evaporate faster, but your data showed that non-chlorinated water evaporated faster.
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.
As a result, most evaporation actually occurs at night. This might seem counter-intuitive, but the reason is that at night the pool water is relatively warm, but the air temperature has dropped. What is this? Therefore, the difference between the air and water temperatures is greater – thus, more evaporation occurs.
Install Windbreakers
A 7 mph wind has the potential to increase evaporation losses by 300%. Break the wind by installing fences, trees, and shrubs around your backyard pool to reduce evaporation losses. BONUS: Install drought-friendly plants in your backyard to save even more water.
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.
Look closely at the filter, pump, heater, and pipe valves, which is where leaks often tend to occur. If you have a vinyl pool liner, look for tears or separations around the fittings, lights, steps, and corners.
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.
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.
Pool Losing Water After Heavy Rain
Due to a heavy rainstorm, water loss is more common with vinyl liner pools that can be damaged, come loose, or float to the top. With other types of inground pools, it is vital to get the water level down. If not drained, the water balance will change, causing cloudy water and more.
If you decide to place the water in a jug that's left open in the refrigerator, the chlorine should evaporate completely within 24 hours. For quicker evaporation times, leave the water at room temperature.
For an even easier and quick estimate, many people suggest using a linear loss rate of 0.25 inches of water per day during the summer. Using this rule of thumb, a typical 500 square foot pool may lose about 78 gallons of water per day.
As the temperature of your pool's water gets colder, the differential pressure between the water and the air increases. This speeds up the rate of evaporation. In addition, lack of humidity and wintertime dry air can also increase evaporation rates. The humid air during the summer keeps more water in your pool.