Passing . . . failing . . . it’s like school all over again! You’ve recently had or are thinking about having a hydrostatic pressure test conducted on your home plumbing drain lines. How do you know if it passes? How do you know if it fails? What happens next? Let’s throw in an ACK! for good measure.
All completely good and normal questions. And unlike school report cards, this won’t go on your permanent record so there’s no need to worry. Hydrostatic pressure testing is all for your benefit and peace of mind.

At Anchor Foundation Repair, we conduct hydrostatic tests on plumbing drain lines for nearly every foundation repair project we complete. Since our business start in 1985, we have performed this test on thousands of homes in the Bryan, College Station, and Brazos Valley areas. Since we do them all the time, we can easily explain the results of hydrostatic pressure testing to you.
This article will quickly explain the role of hydrostatic testing in the world of foundation repair. Then we detail how you know what the results of the test are and what needs to happen next.
What is a Hydrostatic Plumbing Test and Why Is it Important?
We’re sort of assuming at this point that you know basically what hydrostatic testing is. But if you don’t here’s a couple of way more detailed articles for you in case you need them:
Why Do I Need a Hydrostatic Plumbing Test During Foundation Repair?
What Is a Hydrostatic Pressure Test In Foundation Repair? 4 Steps

It’s cool too if you don’t want *all that much* background stuff, so in a nutshell here are the absolute basic principles you need to know.
- The purpose of hydrostatic testing is to check your drain line system for leaks
- This is important because you really don’t want undetected and unrepaired leaks under your house, especially if you are going through the process and expense of getting your foundation repaired.
- The testing process consists of isolating your house from the rest of the public sewer and filling up the drainage system under your home to see if *holds water*.
What Happens if My Home Fails the Hydrostatic Plumbing Test?
Now that you’re up to speed with the basics, we are checking to see if your isolated drain lines hold water or not. Your home *fails* the hydrostatic pressure test if you see the water level drop in lines during the test. Dropping water levels mean a leak is present.
Alas, the test has failed. But don’t worry, there are do-overs later . . .
If the water drops quickly and visibly, you probably have a big leak or several leaks under your house. If the water drops slowly, you have a small leak somewhere under the foundation.
So what happens if your home fails the hydrostatic plumbing test? Well, a couple of things have to happen. First, the location of the leak needs to be found, and then the leak or leaks need to be fixed.
Pinpoint the Location of the Leak or Leaks

You know there’s a leak, but it could be anywhere at this point. The plumber or repair team will work to further identify the location of the leak by isolating out smaller sections of the drain line system to test individual branches of pipes.
Think of a home drainage system like a tree. The trunk of the tree is the main line heading out towards the sewer, but the branches of the drainage system head in different directions under your home.
One branch might head towards your kitchen and laundry area, while another branch allows for drainage from your bathrooms on the other side of the house. Every home is different on this but hopefully, you get the idea.
The branches can be isolated from one another at intersections in the pipes and just one section can also be tested in the same manner to find out exactly where the leak is that needs repair.
Access and Repair the Leaking Drain Line Failure Points
So, once the leak (or leaks) are located, a plumber will need to access those areas to fix them. One way to access the leaking plumbing points is by under-slab tunneling which is less disruptive to a homeowner and keeps dirt and mess outside the home.
Another way to access under-slab leaks is by breaking up the slab foundation from above. This can damage flooring, make big holes and big messes. Sometimes homeowners choose this option or don’t know about tunneling. But whichever way the plumbing failure points are reached, they must be repaired before moving on to the final steps of foundation repairs.
Repeat Testing to Ensure the Repair is Complete
It’s a good idea to test the repairs again to double-check that no leaks were missed and that all the repairs are holding before moving on as well. This is the do-over I was talking about earlier.

The “repair and test again” process might happen more than once if leaks continue to be detected and repaired. All the leaks have to be fixed . . . oh, did I say that already? Well, it’s important and well worth repeating.
What Happens Next if My Home Passes the Hydrostatic Test?

So then what does it mean if the water levels don’t drop? (I hope this isn’t a surprising answer.) It means your home has successfully passed the hydrostatic test and you don’t have any more leaks under your house.
If your home *passes* the test, you should have a tiny party inside your head and maybe do a little imaginary dance with ribbons. It’s a very good thing if your home is leak-free and no repairs (or no further repairs) are needed on the plumbing drain lines. That means the plumbing bill can be totaled up and will not increase further.
Yes, you do have to pay for the plumbing repairs separately from the foundation repairs. It’s not included in the cost or scope of work of foundation repairs. The foundation guys fix the foundation part, and the plumber guys fix the plumbing. But either can or may conduct the hydrostatic pressure test as part of their services.
What happens after the passing hydrostatic plumbing test is that the foundation repairs can be completed with the finishing steps of backfilling any tunneling routes and holes created during the repair process. Then, the mud-pumping stage can begin to secure and lock in both the plumbing repairs and the raised foundation.
Does Anchor Foundation Repair Use Hydrostatic Testing?

Great question, we’re so glad you asked! We always conduct hydrostatic plumbing testing with all foundation raising jobs. Because we think it’s that important and you should never skip it. Using the hydrostatic test is just one of the service features that set us apart from other foundation repair companies.
At Anchor Foundation Repair, we believe in doing the most thorough job possible and have been doing so since 1985. That means we never cut corners and skip important double-checks to make sure that your home is leak-free after foundation repair.
We also can’t skip the hydrostatic testing because next we use mud-pumping in our foundation repair projects as well and there cannot be leaks or things go wrong. Check out this article now for more details on mud-pumping in foundation repair.