how much water evaporates from a pool

John W. Lund Evaporation Equation

Full Answer

Why is my pool losing water?

Why is my inground pool losing water?

• Evaporation. A typical pool naturally loses about a quarter of an inch of water to evaporation on a daily basis. ...
• Splashing. Excessive splashing can lead to a considerable drop in your swimming pool’s water level. ...
• Pool leaks. Sometimes, the water loss really is caused by an actual pool malfunction. ...

How much heat is lost from pool water evaporation?

This is also why heated pools lose most of their heat overnight. How much water is lost to evaporation in a pool? Normally pools see ¼ – ½ inch loss of water per day due to evaporation. This is roughly 2 – 4 inches per week. For a normal sized pool you will loose 25,000 to 50,000 gallons of water per year due to evaporation.

How do I calculate how much water is in my Pool?

To calculate how many gallons of water are in a square or rectangular pool will depend if it is a constant depth or a variable depth. For example, if your pool has a constant depth, multiply it with the length and width of the oasis to get the total in cubic feet. Then, multiply the total measurements by 7.5 to calculate the sum in gallons.

How much evaporation in a pool is normal?

T he 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. What are high evaporation rates?

How much water should my pool lose to evaporation?

How Much Should a Pool Evaporate in 24 Hours? 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.

Why is my pool water evaporating so fast?

The colder the water in your pool becomes, the greater the pressure difference grows between the water and the surrounding air. As this difference increases, the evaporation process speeds up — especially in the dry, low-humidity air that winter so often brings.

Why is my pool losing 2 inches of water a day?

Losing more than ½” of pool water per day indicates you likely have a leak in your pool's structure or your pool pump system. You should call your pool service for a thorough leak inspection. You might not be able to keep up with refilling your pool at this point.

How often should you need to add water to pool?

Normally pools see ¼ – ½ inch loss of water per day due to evaporation. This is roughly 2 – 4 inches per week. For a normal sized pool you will loose 25,000 to 50,000 gallons of water per year due to evaporation. This means I was putting a hose in the pool every 7-10 days to fill the pool.

How do I know if my pool is leaking or evaporating?

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.

How do I stop my pool from losing water?

Here are 5 methods to drastically decrease the amount of water you use in your pool.Use a pool cover. ... Check for leaks and repair ASAP. ... Remove or deactivate unnecessary fountains and waterfalls. ... Reduce water temperature. ... Splashing & drains.

How can I tell where my pool is leaking?

Check the waste or backwash line for water consistently running. One inch of your pool water can equal 500 gallons. Check downhill from a pool, looking for weepers where underground leakage is surfacing. Check for soft or wet spots in the yard, on the side of the pool where the plumbing returns water to the pool.

Why is my swimming pool losing water?

Pools lose water gradually, so water-loss can often be left undetected until it escalates into a serious problem. It's natural for pools to lose water due to evaporation, varying in speed depending on the humidity, temperature, wind conditions, use of pool heater, or the rate of use of the pool.

How to keep pool water evaporation level?

Long story short, even if you live in a hot climate with high evaporation rates, you can keep your pool evaporation levels closer to the two millimeters per week mark by using a solar pool cover and being mindful of how you use water features.

Why Does Pool Water Evaporate?

From a scientific standpoint, evaporation happens when water molecules begin moving around so quickly that they bump into each other, releasing water vapor molecules into the atmosphere.

What happens when air pressure is high in a pool?

The higher the air pressure on the surface of your pool, the less likely your pool water will evaporate quickly. As its name suggests, the air pressure literally presses down on the water’s surface, making it difficult for water molecules to escape.

How to reduce evaporation in a pool?

Even better, use a solar cover if you can. That way, your water will heat up so that it’s closer to the air temperature, which will reduce evaporation rates.

What factors determine the evaporation rate of a pool?

As I mentioned earlier, numerous factors determine a pool’s evaporation rate, and climate is the most important. Furthermore, your pool will likely change its evaporation rate throughout the year, depending on the environment.

How much water does a pool lose?

Your pool may lose anywhere from two millimeters to two inches of water every week as a result of evaporation.

How to increase water evaporation?

Shut off water features with aeration. Fountains and misters are fun to look at, but they significantly increase evaporation rates.

How to calculate evaporation rate of water from pool?

The evaporation rate of water from a swimming pool is fairly easy to calculate; given you have access to a psychometric chart or a water vapor tables. W= (A (69.4+30.8 (V)) / Y ) (Pw-Pa) W = lb / hr of evaporation. A = surface area of the swimming pool. V = mean wind velocity (mph). Y= Latent heat (approx. 1000). Pw – Sat. Press at Room Air temp (in Hg). Pa – Sat. Vapor press at water temp (in Hg)

How to prevent pool from evaporating?

A few fun facts: 1 You will lose more water in the spring and fall than in the middle of summer. When water temperatures warm up during the day and cool significantly at night just watch the steam rising. (I often visualize this as $$ signs floating right out of the pool.) 2 Liquid Solar Blankets and actual solar blankets are a great way to prevent a significant amount of evaporation. 3 A call to your local pool professional to troubleshoot your questions may help give you an idea what is normal for your area. 4 Leak detection experts can use equipment to locate and find leaks through the use of underwater microphones and other technical equipment.

Why does my pool lose water?

Water loss due to splash out or wind will depend on any water features that you may have, and any areas where water is raised and falling back into the pool where wind could pick it up just a bit. People and pets playing in the pool will also cause some of your water loss through normal splashing and swimming activity.

How much water does a pool lose per week?

One municipal water district predicts that water loss of 200-300 gallons per week for a medium-sized pool — about 2%-5% of typical pool volumes in southern states.

When does water lose more water?

A few fun facts: You will lose more water in the spring and fall than in the middle of summer. When water temperatures warm up during the day and cool significantly at night just watch the steam rising. (I often visualize this as $$ signs floating right out of the pool.)

How to test a pool bucket?

To perform the bucket test: Take a 5-gallon bucket and make a mark with a permanent marker at about the halfway point. Fill the bucket with (pool water so it’s the same temperature) water up to that point, and set the bucket right beside your swimming pool.

What happens to a pool when it evaporates?

Evaporation is when liquid turns into a gas or vapor. This process happens to almost any body of water under the right conditions, including swimming pools. This means, as a pool owner, you lose a measurable amount of pool water every day through evaporation. Several thousands of gallons of water per year for an average residential pool, in fact.

Why Does Pool Water Evaporate?

There are multiple conditions that govern the rate of evaporation for any body of water, including swimming pools.

What to do if pool water is slowly depleting?

Don’t Sweat It! All pool owners deal with evaporation to some degree, so don’t panic if you find your water level slowly depleting. Just get a handle on what your evaporation rate should be, and be prepared to take swift action if you suddenly start losing more water than expected.

How to check pool level with a black marker?

Fill a bucket with the water from your pool. Using the pool steps or possibly the shallow end of the pool, place the bucket in the water so the rim is just above the waterline. On both the inside and outside of the bucket, mark the water level with a black marker or some tape. Wait a full 24 hours.

What does it mean when the water level on the inside of a bucket is higher than the outside?

If, after performing the test, the water level on the inside of the bucket is noticeably higher than on the outside, you probably do have a leak .

What is the best way to stop water evaporation?

Use a regular pool cover. A pool cover or even a safety pool cover will do a great job blocking water evaporation since water particles can’t escape through solid material

Where is the leak when the pool pump is off?

If you lose more water when the pump is off, the leak will likely be found in the return lines. If you lose less water when the pump is off, the leak will likely be found in the skimmer and main drain. If you lose the same amount of water when the pump is off, the leak will likely be found in the shell, pool liner or fittings.

How Do You Calculate Water Loss in Your Swimming Pool?

If you are constantly having to refill your pool, you will first want to find out exactly how much water you are losing per day before deciding what to do next.

What Increases The Rate of Evaporation?

Evaporation is very dependant on where you live and the seasons. Air temperature and humidity, water temperature, exposure to sunlight, and prevailing winds all have a huge impact on evaporation rates.

How to Reduce Water Evaporation in Swimming Pools

Let’s save ourselves some time and money (and environment) by doing as much as we can to reduce water evaporation. It’s the right thing to do.

Conclusion

It is quite normal to lose 2 to 4 inches of water every week. However, anything more than that means that you very likely have a leak and this will need to be checked by a professional.

Why does pool water 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.

How much water does a pool lose in a day?

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.

Why is the water in my pool humid?

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.

What is the difference between dry and humid air in a pool?

As a result, humid air keeps water in the pool, while dry air allows pool water to evaporate.

What is the best way to determine if a pool has a leak?

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.

Does wind affect pool water?

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. Try Our Swimming Pool Water Loss Calculator Today!

How much evaporation is normal in a pool?

How much pool evaporation is normal? The standard evaporation rate is 20mm per day. Of course, the amount varies based on many factors like climatic conditions and pool size.

Why is evaporation high in commercial pools?

Commercial pools experience high evaporation rates due to frequent use. Whenever swimmers are in the water, they tend to splash out the water from the pool. When building your pool, construct efficient gutters on the pool sides. This way, you can prevent water loss.

How much water does a pool lose per day?

Usually, pools lose water at specific rates depending on the weather conditions and pool chemicals. However, the standard rate of evaporation is 20mm per day. Of course, the amount varies based on many factors like climatic conditions and pool size.

Why do you need a pool in your yard?

Even so, there are a lot of maintenance procedures that come with swimming pools. One of the ways of taking care of your pool is to reduce the pool evaporation rate.

How to measure pool water level?

What you have to do is take a portion of your pool water and fill it in a bucket of medium size. Determine the water level in the bucket and mark the area. You can also use a calibrated bucket. Leave the water outside near the pool and measure the quantity of the water after a day.

Why does my pool pump leak water?

With time your pool surfaces and floors develop cracks, thus causing water loss. Also, your pool pumping systems could malfunction and lead its leakage.

Can a pool be exposed to sunlight?

It is usual for outdoor pools exposed to sunlight to experience evaporation. But you have to identify the standard evaporation rate for your pool. So, testing for the evaporation rate requires the pool owner to use a practical procedure.

How to measure evaporation rate of pool?

Measuring the evaporation rate is relatively simple. First begin by using a ruler or tape measure to measure the distance from the pool deck to the water's surface.

How does evaporation affect a pool?

Left unchecked, evaporation affects a pool's chemical balance and the integrity of the pumping and filtration systems.

What is the EPA evaporation equation?

The EPA Evaporation equation was developed to estimate evaporation from the surface of a pool of liquid that is at or near ambient temperature. Please note that the equation as been modified from its general form to be applicable to calculating evaporation from swimming pools.

How to convert evaporation rate to gallons per day?

For example, if your measurement was in inches per day, simply divide that by 12 to convert it to feet per day. Next, multiply that value by the surface area of your pool and then by 7.48 to get gallons per day.

How much water does a pool lose?

Depending on where you live, an average-sized residential pool with a surface area of 400 square feet could lose as much as 10,000 gallons of water each year due to evaporation! If left unchecked, evaporation can affect the pool's chemical balance as well as the integrity of the pumping and filtration systems. Of course, this will also end up costing you money as well! Given this proposition, it is a worthy investment of time to estimate just how much water your pool could lose to evaporation each year.

Why is evaporation so difficult to estimate?

This is because the rate of evaporation is actually controlled by many factors including, temperature, air pressure, wind speed, and humidity. Several equations exist that can be used to predict evaporation.

Why cover a pool when not in use?

Covering your pool when it is not in use will save you a significant amount of money and reduce your greenhouse gas emission.