Pool Water Level and Evaporation in a Texas Summer

How much water does a pool lose in a Texas summer?

About a quarter inch a day is the common figure. PoolResearch.com says average evaporation is “around 1/4 inch of water per day,” or roughly 2 inches a week. It gives a range of two millimeters to two inches a week.

PoolResearch’s article is not specific to Texas. Its sample chart is for a 400-square-foot pool with minimal use, no rain and a dry climate. It shows 10 inches (2,469 gallons) lost in summer, 7.8 inches in spring, 5.7 in fall and 2.8 in winter. Use it as a model, not a promise.

DFW summers are hot. The National Weather Service counted 52 days at or above 100 F so far in 2026 as of September 22. Hot days speed evaporation.

What makes the water level drop faster?

PoolResearch says climate is the biggest factor. It names:

• Sun and solar radiation
• Wind
• Temperature
• Rainfall
• The gap in vapor pressure between water and air

It also lists human factors: whether the pool sits in sun or shade, swimmer traffic, splashing, and fountains or other water features. Splash-out and backwashing also lower the level, but those are not evaporation.

Is it evaporation or a leak?

Do a bucket test. PoolResearch describes it this way:

1. Fill a bucket with pool water and mark the level.
2. Set it on a pool step with the rim slightly above the water line.
3. After 24 hours, mark the new level.
4. Compare the loss in the bucket to the loss in the pool.

PoolResearch says, “if the bucket loses less water than your pool, a leak is likely the culprit.” Run the test when no rain is forecast. Our bucket test guide has the full steps.

PoolResearch adds a second test with the pump off. Comparing the two results can point to the return lines, the skimmer or drain, or a structural problem in the shell, liner or fittings. Finding and fixing leaks is a separate trade. Marina Pool Services does not list leak detection, so ask a leak specialist for that work.

What does a low water level do to the equipment?

A low level can pull air into the system. That can make the pump lose prime and run dry. See our post on why a pump loses prime. A dry-running pump can fail. Keep water high enough that the skimmer draws water. Your pump and filter manuals describe the right level for your setup.

An automatic water leveler tops off for you. That is handy, but it can hide a leak. If your bill jumps or the leveler runs a lot, run the bucket test.

Can I top off my pool during a drought?

Often yes, with limits. Rules vary by city and stage, and they change. As of October 2026, Keller’s page says:

• Stage 1 restricts draining and refilling swimming pools.
• Stage 2 prohibits filling pools with automatic fill valves.
• Stage 3 prohibits draining, filling or refilling pools, but allows filling existing pools to maintain levels. Pools may not be refilled with automatic fill valves.

Euless’s page shows no restrictions while its reservoir system is above 75 percent. It listed 81 percent on October 21, 2026. Check your own city before you fill. See water restrictions in our glossary, and our post on high CYA and drought rules.

How do I cut water loss?

1. Use a cover. PoolResearch says covering the pool when not in use “significantly” reduces evaporation. Solid covers cut the exposed surface. Solar covers warm the water closer to air temperature, which reduces evaporation too.
2. Turn off water features when you are not using them.
3. Check your evaporation loss weekly. Mark the level with tape at the tile line.
4. Fix leaks early. Water loss over two inches a week deserves a bucket test.
5. Keep up weekly service. A tech who sees the level every week spots a change.

Does evaporation change my chemistry?

Yes. When water evaporates, the minerals stay behind. The leftover water gets more concentrated. That is plain physics, not a measured figure. High calcium leads to scale. Our post on calcium scale on pool tile covers it. If you top off with hard tap water, hardness rises over time.

Marina Pool Services’ weekly service covers water balance, including calcium hardness, plus emptying baskets, backwashing filters as needed, and vacuuming and brushing as needed. See the pool maintenance services page and the weekly service page. The North Texas pool care guide covers summer in more detail.

How do I track my water level?

A simple log makes small changes visible.

1. Mark the water level against the tile or skimmer opening with painter’s tape.
2. Check it on the same day each week, at the same time.
3. Note the weather. Hot, windy days will show larger drops.
4. Note any rain, big parties or backwashing.
5. If the loss runs well above two inches a week, run the bucket test.

A log also helps your service tech. It shows whether the level is following the weather or following something else.

Next step

If your water level keeps dropping, see the pool maintenance services page, then call Marina Pool Services at (817) 896-1120 or use the quote form at /contact.