pro sewer logo 1 e1647380069295 (1)
(425) 478-3133
pro sewer logo 1 e1647380069295 (1)
(425) 478-3133

Sewer Hydrostatic Inspection: How It Works And Why It's Important

image 4

A sewer hydrostatic inspection is an important part of routine sewer maintenance. During a camera inspection, homeowners can see any problems that may have occurred as well as get a good look at their entire drain system.

What is the Hydrostatic Test?

No one wants a sewer pipe that is leaking. But sometimes you can't help it. As a homeowner, it's important to know when your piping is leaking so that water damage doesn't accumulate and you don't have to pay a lot to fix it. So, if a leak is suspected, an inspector may do something called a hydrostatic test, which is a water pressure test used to find leaks in a home's pipe system.

Hydrostatic testing is a quick and easy way to check the water level in your home's pipes for leaks. For a hydrostatic test, the pipe being looked at is filled with water (which creates pressure) and then the level of pressure is watched for changes. If the pressure goes down, it means that there is a leak in the system. If you think your home has a leak, you must do hydrostatic testing to find out if there is a leak under your slab.

When you buy a new home is another good time to use hydrostatic pressure testing. Most of the time, the current owner of the home doesn't know if there are any leaks in their system, and this test will give them the chance to fix them before the sale. Residents can avoid big surprises in the future by using pipe pressure tests. Nobody wants their home's value to go down or for leaks that go unnoticed to cause them to need a lot of work.

Also, if you just leveled the foundation of your home, the hyperextension of your home's pipes can cause leaks in the fittings and couplings, which you should fix right away. After having work done on your foundation, it's always a good idea to have a hydrostatic test done.

How Does Hydrostatic Testing Work in a Home's Sewer System?

image 2

Trees are always looking for water sources that they can depend on. They send their roots everywhere in search of water. Sewer pipes are a good place to get water. The tree sends tiny roots through the smallest hole. If it finds a way in, the root will start to get water from where it got in. This causes the root to grow, which makes the opening get bigger. Over time, the roots can break the pipe by making cracks in it.

Sewage experts can find these hidden leaks with the help of hydrostatic testing. The first step is to find the cleanout on the drain line. The inspector puts a test ball that is inflated into the cleanout. The ball is blown up to block the sewer line. This is usually done near the edge of the foundation.

Because the main sewer line is clogged, the inspector fills it with water all the way to the top edge of the slab and waits. The inspector waits to see if the water level starts to go down. If it does, there is a leak present.

The next step is to find where the water is getting in. One way to find the leak is to put a video camera down into the pipes under the slab. It also lets you check out how these pipes are doing in general.

Why We Use Hydrostatic Testing

A large part of what we do is find leaks. This is why we test with hydrostatic pressure. It helps us find these hidden leaks and fix them.

Hydrostatic testing is done to find out if a house or building with a sewer system has pipes that leak. A cast iron sewer system, which is more than 50 years old, is blocked and filled with water by putting test plugs into the cleanouts. The water is seen in an open toilet drain. A drop in the water level means that the old pipes are leaking.

When Should You Run A Hydrostatic Test?

image 3

Leaks in sewer lines can be caused by things like tree roots growing into the pipes, old pipes, and soil that moves. When you notice strange changes in your home's piping, you should use a static test to find leaks. Leaky pipes under your house could cause any of the following:

• Cracks in the foundation of your house

• Cost of water going up

• Stinky smells

• Floors or carpets that are wet

• Growing mold

• Yard full of septic waste

Leaking sewer pipes can do a lot of damage to your home's foundation and sewage system if you don't fix them. If you think you have a leak, you should have a hydrostatic test done as soon as possible.



A hydrostatic pressure test is done on the sewer system of a home or building to find out if there are any water leaks in the piping system. A test ball that can be inflated is put into the main sewer line cleanout of a building or home. 

The main sewer line is then blocked by the inflated test ball. The sewer system is then filled with water up to the slab level. For up to 15 minutes, the water level is watched. There are water leaks in the sewer system if the system doesn't fill up to the slab level or if the water level starts to go down. The next step in figuring out which sewer lines are leaking is to use a video camera to look inside the pipes.


A sewer pipe or drain line camera inspection of a sewer system is done with state-of-the-art in-line sewer or drain video camera equipment. The camera is put into a sub-slab drain system through existing cleanouts, roof vents, or toilet drains to look at and analyze its condition. 

With a sewer camera inspection, the exact location of any blockages, breaks, stoppages, or deteriorated pipes can be found, as well as an idea of how deep the sewer pipe is.


For leak detection, we use a combination of sewer video camera pipe inspection and hydrostatic pressure testing to isolate and test different sections or areas of a sewer system to find the exact location of water leaks in the system. 

Inflatable test devices are put into the system through existing cleanouts, roof vents, and exposed toilet drains to do hydrostatic tests on parts of the sewer system that are not connected to the rest of the system. During the process, an in-line sewer video camera is used to help place test balls all over the system and map out how the sewer system is set up.

How Often Should Hydrostatic Testing Be Done?

Hydrostatic testing should be done at least once per year but no more than twice per year depending on what kind of product you store and how often it requires maintenance during that time period (for example: every two years instead).

It should also be done if you suspect you have a leak in your system, or if you are wanting to buy or sell a home and ensure the sewage system is up to par.


After reading this guide, you should be able to recognize how a sewer hydrostatic inspection works, and be prepared when it is time to have one completed. 

When in doubt, reach out to Pro Sewer Repair! And contact us for any sewer inspections!

Do you want a free estimate?

Recent Posts

Sewer Lateral Lining: The Complete Guide to Sewer Lateral Lining
When it comes to protecting your home from the risk of sewer lateral overflow, there are several affordable and sustainable…
What is Pipe Bursting: Everything You Need to Know
When it comes to infrastructure, there are seldom easy solutions. Roads, water mains, and other crucial components of a city’s…
Sewer Inspection for Home Purchase
When you are in the process of buying a home, it’s important to maintain a positive outlook. If you’re looking…
What Customers Say

Professionals You Can Trust

I hired Pro Sewer Repair to replace my sewer line. Their estimate was much more reasonable then Pro Sewer fixed a large break in our sewer line where it joined the city mainline. They handled this large job effectively, cost-efficiently, and were great to work with. Jamie and Rob were awesome to work with on scheduling and responsive to questions, and the team (Jason and James) did a great job with the work. Would use them again and will recommend to friends.

Sam R. | Seattle, WA

It's Sewer Repair Expertise That Counts!

Simply call us if you have any sewer issues, and we will assist you!

Pro Sewer Repair is rated 5 out of 5 based on 32 reviews from around the Web.