Pools leak everywhere. But in the Greater Houston area, certain causes show up far more often than the national average — because of our soil, our weather cycles, and the age of our housing stock. After years of leak detection work from Katy to The Woodlands to Sugar Land, these five account for the majority of what we find.
1. Shifting clay soil under the plumbing
Houston sits on expansive clay. It swells when wet and contracts when dry, and it does both several times a year. That movement stresses the PVC slip joints buried under your deck and yard. Over years, those joints either crack or pull apart at the glue line.
The result: a plumbing leak you can't see from the surface. The water disappears underground and the deck stays dry. The only way to confirm it is pressure-testing each line individually to see which one drops.
This is the #1 cause we see in older Cypress, Katy, and Spring pools, where the pool was built 15–25 years ago and is now hitting peak soil-stress age.
2. Skimmer separation at the throat
Skimmers are concrete-set into the deck, but the skimmer body itself is plastic. Over time — especially with deck movement — the plastic separates from the concrete at the throat (the opening you see when you lift the lid). Water flows in but a portion of it escapes around the body before it reaches the line.
Telltale sign: the water keeps dropping until it sits just below the skimmer mouth, then stops. That's almost always a skimmer leak, and it's usually a same-day repair.
3. Return line cracks at the equipment pad
Houston summers hit equipment pads hard. UV light, heat, and freeze-thaw cycles (yes, we get freezes — and the pipes aren't always insulated) cause PVC at the pad to become brittle. The most common failure point is the return manifold, where multiple lines tee together.
You'll often see this as a slow drip under the heater or a wet spot under the filter. Sometimes it's invisible — the leak is on the buried side of the fitting.
4. Light niche leaks
Pool lights sit inside a niche behind a gasketed faceplate. The conduit running from the niche to the junction box at the deck level can leak — either through the gasket, around the conduit, or through a crack in the niche itself.
This one is sneaky. The pool drops to the bottom of the light, then stops. Many Houston-area homeowners assume the light is "just old" and drain part of the pool every season to compensate. It's almost always a fixable leak.
5. Worn pump shaft seals
Not technically a pool leak — but a pump shaft seal failure looks like one. Once the seal is worn, water drips from underneath the pump while it runs. That water goes into the pad concrete or onto the ground and vanishes. The pool drops; the deck doesn't look wet.
Houston's heat and the salt systems many pools run on accelerate this. We check the pad on every leak call before assuming the pool itself is the problem — because if it's the pump, draining the pool to look for a leak that isn't there is an expensive mistake.
What to do if you're seeing water loss
Run a bucket test first to confirm it's a leak and not evaporation. If it is, book an appointment — we cover all of Houston, Katy, Cypress, The Woodlands, Sugar Land, and the broader 100-mile radius, and most jobs are diagnosed in a single visit.