Hydrostatic Sewer Testing
Pressure testing to detect sewer line leaks under your foundation. Required for many home sales.
Find the Leak Without Guessing.
Your home inspector said everything looks good. The general plumber said the drains are fine. But you've got a crack in your foundation and nobody can tell you if the sewer is leaking under your slab. A hydrostatic sewer test is the only way to know for sure. We seal the sewer line, fill it with water, and watch the water level. If it drops, you have a leak under the slab. Simple as that. No guessing, no maybe. This test matters most when you're buying a home, dealing with foundation issues, or trying to figure out why your water bill keeps climbing. Cole's Plumbing has been performing hydrostatic tests in the DFW area for 25 years. We know what the results mean and we'll tell you straight whether you have a problem or not.
When You Need This
Any of these sound familiar? Call us. Small problems don’t stay small.
- Foundation cracks and you suspect a sewer leak underneath
- Buying a home and want proof the under-slab plumbing is sound
- Insurance company requires a hydrostatic test for a claim
- Unexplained water bill increases with no visible leaks
- Foundation repair company recommended testing before their work
How It Works
The test itself takes about 2 hours. Here's what happens.
Seal and fill
We plug the main sewer line at the cleanout and fill the entire system with water through a roof vent. The water level is set to slab height. Our service call covers the initial visit and assessment.
Wait and measure
We let the water sit for 15 to 20 minutes and monitor the level. If the water level drops, there's a leak somewhere under the slab. If it holds, your under-slab lines are intact.
Isolate if needed
If the test fails, we systematically isolate sections of the sewer system to pinpoint which line is leaking. This tells you exactly where the problem is, not just that one exists.
Why Cole's
Pass/Fail Clarity
No gray area. The water level holds or it doesn't. You get a definitive answer, not a vague opinion.
Written Test Report
We provide a signed report with test results, suitable for insurance claims, real estate transactions, and foundation repair documentation.
Isolation Testing Included
If the main test fails, we isolate sections at no extra charge to identify which specific line has the leak. Most plumbers charge separately for this.
200+ Five-Star Reviews.
Chad came out the same day we called. He looked at our water heater, told us exactly what was wrong, gave us a price, and got it done that afternoon. No surprises on the bill. We've used other plumbers in the area and this was by far the best experience.
The last plumber we called tried to sell us a whole new system when all we needed was a valve replacement. Chad was honest about what the actual problem was and fixed it for a fraction of what the other company quoted. That's rare.
We had a slab leak and were panicking. Chad walked us through the whole process, explained what he was doing at every step, and his price was fair. He even followed up the next week to make sure everything was holding. This is the only plumber we'll call from now on.
Straight Answers.
It tells you whether your under-slab sewer lines hold water or leak. That's it. Pass or fail. If they leak, isolation testing tells you which specific line has the problem. It's the most definitive test for under-slab plumbing integrity.
If the home is on a slab foundation and over 15 years old, yes. Standard home inspections don't test under-slab plumbing. A failed sewer line under a slab can be costly to repair. A hydrostatic test before closing is cheap insurance.
About 2 hours total. Setup and filling takes 30 to 45 minutes. The hold period is 15 to 20 minutes. If isolation testing is needed, add another 30 to 60 minutes. Most tests are done in a single morning.
No. We're just filling the existing pipes with water, which is what they're designed to hold. The test pressure doesn't exceed normal operating conditions. If a pipe fails during the test, it was already failing during daily use.
We identify exactly which line is leaking through isolation testing. Then we give you repair options: spot repair through the slab, reroute around the slab through the walls, or tunnel under the slab. Each option has different costs and tradeoffs, and we lay them all out.
Other Jobs We Handle
One call, one team. Every job is licensed, insured, and backed by a 1-year warranty on parts we provide and install, plus labor.
Need Hydrostatic Sewer Testing? Call Now.
Same-day service when you call before noon. Service call fee applied to any work you approve.