How Do I Prevent Water Evaporation in Hot Weather?

Use a solar cover to minimize water loss and reduce evaporation during hot weather.

Why Water Evaporation Happens

Water evaporation is a natural part of pool ownership, but it increases dramatically in high temperatures. When heat combines with direct sunlight, low humidity, and wind, water evaporates at a faster rate.

Factors That Speed Up Evaporation:

• High air temperature

• Direct UV exposure

• Low humidity

• Wind or breezes across the water surface

• Heated pools running at high temperatures

On average, a pool can lose a quarter inch to half an inch of water per day in summer. That adds up to hundreds of gallons each week. In dry, desert climates, losses can exceed two inches in just a few days if the pool is uncovered.

How to Tell If Evaporation Is the Problem

Sometimes what looks like evaporation is actually a leak. It’s important to rule that out first so you’re not adding water unnecessarily.

Check for Signs of Evaporation vs. Leak:

• Water loss is steady and only happens during the day

• No soggy spots or puddles around the pool shell or equipment

• Plumbing and filter pad are dry and free from drips

• Water level stabilizes when the pool is covered for 24 hours

Try the Bucket Test

1. Fill a bucket with pool water and place it on the pool step.

2. Mark the water level inside the bucket and the pool water level outside.

3. Wait 24 hours without using the pool.

4. Compare the water loss. If the pool level drops significantly more, you likely have a leak.

Simple Ways to Reduce Pool Water Evaporation

1. Use a Pool Cover

Covers are the most effective defense against evaporation.

• Solar covers trap heat, block sunlight, and reduce evaporation by up to 95 percent.

• Mesh safety covers reduce leaf debris and slow down evaporation while allowing some drainage.

• Automatic retractable covers are great for convenience and safety but require upfront investment.

A well-fitted cover also reduces chemical use and heat loss.

2. Install a Wind Barrier

Wind increases evaporation by pushing away the layer of saturated air above your pool’s surface. A barrier keeps this layer stable and slows water loss.

• Use fencing, hedges, trellises, or vinyl wind screens.

• Position them on the side that gets the most wind.

• Make sure the barrier is at least 3 to 5 feet tall.

3. Lower Pool Water Temperature

The warmer your water, the faster it evaporates. If you have a heater, reduce the setting by a few degrees.

• Turn the heater off during heatwaves or midday hours.

• Only heat your pool in the early morning or evening.

• Use a solar cover to retain heat during cooler nights.

Use Liquid Solar Covers

These are invisible films that float on the surface and reduce evaporation without interfering with swimming.

Benefits of Liquid Covers:

• No need to remove before swimming

• Reapply weekly or after heavy rainfall

• Can be used in conjunction with traditional covers

They are great for irregularly shaped pools or ones that are used daily and hard to keep covered.

Water-Saving Habits That Make a Difference

1. Monitor Water Levels Weekly

Check your pool’s water level every few days in hot weather. A consistent log helps you identify evaporation patterns and catch problems early.

• Mark your skimmer faceplate or tile line with waterproof tape for reference.

• Refill slowly and only when needed.

2. Turn Off Splash-Heavy Features

Fountains, deck jets, and waterfalls expose more surface area and increase splash-out.

• Limit use to evenings or special occasions

• Set timers to run features for only a few hours per day

3. Keep the Pool Clean

Clean water means less frequent backwashing, draining, or chemical rebalancing, which all lead to water waste.

• Skim and vacuum debris regularly

• Brush walls to reduce biofilm buildup

• Use enzymes to help break down organic matter

Equipment Upgrades That Help Reduce Evaporation

1. Variable-Speed Pumps

These run longer at lower speeds, improving circulation while reducing heat buildup and evaporation from stagnant zones.

• Schedule to run during cooler times of day

• Helps spread chemicals more evenly and reduces energy use

2. Automatic Fill Systems

These top off the pool as water evaporates. While convenient, they can mask leaks, so monitor your water bills or install a meter to track fill usage.

3. Smart Pool Sensors

Some sensors now measure evaporation rates, water levels, and temperature. These tools provide data you can use to adjust habits and timing.

Landscaping for Evaporation Control

How your pool area is designed affects how much water you lose.

Add Strategic Shade

• Install shade sails or pergolas

• Use cantilever umbrellas near the shallow end

• Place tall potted plants to create moveable shade walls

Plant Water-Wise Vegetation

• Use drought-resistant shrubs or trees that don’t drop excessive leaves

• Avoid messy or invasive species that increase maintenance

Natural windbreaks from landscaping also double as decorative privacy barriers.

Seasonal Water Loss Management

Evaporation rates change with the seasons. Adjust your pool care accordingly.

Peak Summer Checklist:

1. Cover the pool during the day when not in use

2. Limit heater use

3. Run the pump at night

4. Top off water weekly with a hose filter

Fall Adjustments:

1. Increase skimming as trees drop leaves

2. Use a mesh cover to keep out debris

3. Lower the water level slightly if rains are frequent

When to Call a Pool Professional

If evaporation is unusually high or unpredictable, there may be an underlying issue.

A Pro Can:

• Test and diagnose leaks in plumbing or structure

• Inspect the pump and return fittings for slow leaks

• Recommend equipment upgrades that improve water retention

Staying proactive with professional inspections every few years keeps your pool performing efficiently and leak-free.

Keep Your Pool Full With Smart Evaporation Control

Hot weather doesn’t have to drain your pool or your wallet. Combining covers, good habits, efficient equipment, and smart landscaping gives you the best chance to fight off evaporation. A few adjustments now can save hundreds of gallons, lower your water bills, and extend the life of your pool system throughout the hottest months.