Your pool is losing water. You refill it. A few days later, you refill it again. You're starting to wonder: is this normal, or do I have a leak? In Houston's brutal summer heat, evaporation is real — but it only accounts for so much. If you're consistently losing more than a half-inch of water per day, something else is going on. Here's how to diagnose it and what to do next.
Evaporation vs. Leak: Know the Difference
Evaporation is normal. In the Houston summer — with temperatures regularly topping 95°F and low humidity after a long dry stretch — you can lose up to ½ inch of water per day without any leak at all. That's about 500 gallons per week for a standard 15×30 ft pool. It's a lot, but it's physics.
A leak is different. The water is going somewhere it shouldn't — through a crack in the shell, a failing fitting, a bad O-ring on your equipment, or a breach in the plumbing lines buried under your deck. And unlike evaporation, a leak doesn't slow down when the weather cools. It keeps going, and it usually gets worse.
Warning Signs You Have a Leak
Water loss alone isn't always obvious — especially in summer when you're adding water routinely anyway. Watch for these secondary signals:
You're adding water more than twice a week
In summer heat, once a week is typical. If you're topping off every other day, you're likely dealing with more than evaporation.
Wet spots in your yard near the pool equipment
Soggy grass or mud around your pump, filter, or heater pad — especially when it hasn't rained — often means a plumbing or equipment fitting leak.
Cracks in the pool shell or tile line
Visible cracks anywhere in the plaster, gunite, or along the waterline tile are serious. Even hairline cracks can allow significant water loss over time.
Sinking or lifting deck sections
If water is escaping underground, it erodes the soil beneath your deck over time. Uneven, sunken, or cracked deck sections are a red flag.
Unusually high water bills
If your water bill has jumped and you can't explain it, your pool auto-fill valve may be running constantly to compensate for a leak.
Chemical imbalances that won't stabilize
If you're constantly fighting low chlorine or wildly off pH despite regular treatment, you may be continuously diluting fresh water into a leaking pool.
DIY Diagnostic
The Bucket Test: Your First Step
Before calling anyone, run this simple test. It takes 24 hours and costs nothing.
Fill a 5-gallon bucket with pool water to about 1 inch from the top.
Place the bucket on the first or second step of your pool, so it's sitting in the water.
Use a marker or tape to mark the water level inside the bucket AND on the outside of the pool wall.
Turn off your auto-fill valve. Run the pool on its normal schedule for exactly 24 hours.
After 24 hours, compare the two levels.
Reading the results:If both the bucket and the pool drop by the same amount — that's evaporation. If the pool drops significantly more than the bucket, you have a leak. If the pool drops less than the bucket, your auto-fill valve may be running and masking a bigger problem.
Where Pool Leaks Usually Come From
Most residential pool leaks fall into one of four categories. A professional leak detection service uses pressure testing and dye testing to pinpoint exactly which one you're dealing with.
Shell cracks
Cracks in gunite, plaster, or vinyl liner are the most visible type of leak. They can result from ground movement, freeze-thaw cycles (rare but real in Houston), or structural stress. Even a hairline crack can lose thousands of gallons per month.
Plumbing lines
Buried return and suction lines can crack or separate at joints over time, especially if there's been any ground shifting or root intrusion. These leaks are often entirely invisible from the surface and require pressure testing to locate.
Equipment fittings
The connections at your pump, filter, heater, and chlorinator are under constant pressure and thermal cycling. O-rings and unions fail, especially on older equipment. These leaks are usually easy to spot — look for mineral staining or wet spots around your equipment pad.
Skimmer and return fittings
The skimmer throat seal and the fittings where return jets meet the pool wall are high-failure points. The sealant breaks down over years of UV exposure and chemical contact. A dye test will show the exact breach point.
When to Stop DIY-ing and Call a Pro
The bucket test tells you whether you have a leak. It doesn't tell you where it is. If your bucket test confirms a leak, the next step is professional leak detection. Here's why guessing costs more:
Many homeowners assume the leak is in the shell and start patching visible cracks — only to find the pool still losing water because the actual breach is in a buried return line 12 feet from where they were looking. Professional leak detection uses pressure testing on individual plumbing lines and dye testing at suspected breach points to find the exact location before any repair work begins.
Call a pool professional immediately if: your pool is losing more than 1 inch per day, you see visible cracks in the shell or around fittings, you notice wet or sunken areas in your yard, or your equipment is showing signs of water damage. The longer a structural leak goes unaddressed, the more it erodes the surrounding soil — which can eventually undermine your deck or equipment pad.
Frequently Asked Questions
How much water should a pool lose per day?
Normal evaporation in Houston's heat is typically ¼ inch to ½ inch per day. If you're losing more than that — especially more than 1 inch per day — you likely have a leak rather than just evaporation.
What is the bucket test for pool leaks?
Fill a bucket with pool water and place it on the pool step. Mark the water level inside the bucket and on the pool wall. Run the pool normally for 24 hours. If the pool loses more water than the bucket, you have a leak. If both drop equally, it's evaporation.
Can a pool leak fix itself?
Pool leaks almost never fix themselves. Small cracks in plaster or shell can temporarily seal with debris, but the underlying damage continues to grow. A slow leak becomes a serious structural issue if ignored. Early detection and repair always costs less than waiting.
Think You Have a Pool Leak?
Don't wait. Call Radiant Pools for professional leak detection and repair in Houston. We find it fast and fix it right — before the damage gets worse.
Call Us: (713) 487-9687