Financing Link

Sewer Stoppage & Repair

Main Line & Sewer Clean-Out, Repair, and Replacement by Houston’s best and most recognized licensed plumbers since 1965.

Quality Guarantee

Signs of a Main Line Stoppage

Does foul smelling water come out of your tub or shower drain when you flush your toilet? Do you notice a gurgling sound coming from your toilet when you take a shower?

Does your toilet overflow when you use your washing machine? It may seem like your home has lost its mind, but these are all just signs that there is a stoppage in your home’s main line.

Backed-up Sink

What is a Main Line Stoppage?


Every drain in your home – your sink drains, shower drains, tub drains, washing machine drains, and toilets- are connected to your home’s main sewer line.

When you wash something down your sink, take a bath or shower, wash clothes, or flush your toilet, that waste water goes down a vertical drain line that ties into a larger horizontal main line.

Main lines are sloped so that gravity carries waste water down your main line and into a public sewage or septic system. But if your main sewer line becomes clogged, your waste water will eventually have nowhere to go except for up through another drain in your home, referred to as sewage backup.

First floor tub drains and first floor standalone shower drains are almost always where homeowners first notice sewage backup because they are the closest drains to the main line. If your home doesn’t have a tub or shower on the first floor, then the toilets on the first floor of your home will make gurgling noises, and possibly overflow with water whenever you take a shower, use a sink, or wash clothes or dishes.

Having sewer water come back up through a fixture is a nightmare for some, but John Moore is here to stop the problem and prevent it from ever happening again.

What Causes a Main Line Stoppage?

Main line stoppages are always caused by an obstruction in your main line, and there are several main line obstructions we see over and over again:


Click image to enlarge

Build-up in a Bellied PVC Main Line

Remember how we said that main lines slope so that gravity carries your home’s waste water to a public sanitation system? Well, sometimes this slope gets a belly, or dipped section of pipe, especially if it’s a main line made out of PVC.

How does PVC main line get a belly? A main sewer line is usually one of the first things built when a home is being constructed, so when the foundation of a home is being poured, the weight of all that concrete pushes down on the foundation’s footers, which puts pressure on the ground above where the main line is. Sometimes, this pressure is enough to create a belly in what would otherwise be a perfectly downward sloping main line.

Why does a belly lead to a main line stoppage? Well, we put a lot of sticky things down our drains: petroleum found in soap; toothpaste; and, well, poop.

Usually, water and gravity accompany these waste items so that your main line becomes a water slide of sorts. If your pipe has a bellied section, then the water starts to pool in that area.

Because the sticky unmentionables we mentioned above float in water, they get stuck to the top of the pipe in bellied areas where they build up overtime, which eventually turns into a complete main line stoppage.


Click image to enlarge

Channel Rot or Broken Cast Iron

Before it became standard for main lines to be made out of PVC, they were mostly made out of cast iron that tied into a concrete main line before reaching the public sewer system. If your home was built before the 80s, it more than likely has a cast iron main line.

The major issue with cast iron main lines – and why home builders switched to using PVC – is that cast iron is prone to rotting and snapping. When too much pressure is applied to a cast iron pipe, instead of bellying like PVC, it snaps in half, leading all your sewer water into the ground, which eventually stops your main line with mud.

Cast iron is also prone to “channeling” or rotting from the inside out. The average lifespan of a cast iron pipe is 25 to 30 years before it completely bottoms out. When a cast iron pipe rots all the way through, your waste water will mix with the dirt underneath the pipe, creating a buildup of mud, which can eventually turn into a stoppage.


Click image to enlarge

Tree Roots Intrusion of Main Line

In older homes, it was common to have a cast iron or ABS main line that turned into a concrete main line after passing the edge of the home. Concrete main lines are made out of sections of concrete pipe that connect using bell and spigot joints.

Essentially, one end of each pipe flares out so that the diameter is wide enough for the spigot end of another concrete pipe to go in. After they were laid underground, concrete would be used to seal each section of concrete pipe together. Unfortunately, this method of attaching concrete pipes together leads to offsets, which get worse and worse as the ground swells and shifts over time.

There are two types of offsets: positive offsets and negative offsets. A positive offset is when a section of concrete pipe is lower than the previous section, creating a step down that functions like a waterfall, allowing the waste water to cascade down the pipe. A negative offset is when the bottom of the next pipe is higher than the bottom of the previous one, creating a step-up that prevents waste water from easily moving through the pipe. But no matter if the offset helps or prevents the flow of waste-water, it creates a hole in the main line, which can become a major problem if there’s a tree nearby.

Tree roots naturally seek out fertile soil and nutrients, and the waste you flush down your toilet is rich in nutrients, so it’s not uncommon for tree roots to seek out holes in main lines. Once tree roots find their way into a main line, they will grow and cause a lot of problems like breaking other areas of pipe, and eventually, they will completely obstruct the flow of waste-water, leading to a stoppage.

John Moore’s Main Line Stoppage Solutions

Just as there several things that cause a main line stoppage, there are also several solutions that John Moore has, some that fix the immediate problem, and others that prevent main line stoppages in the long-run.

Clearing a Main Line Stoppage

When there’s nasty water coming out of your tub drain or your toilet is overflowing, the first thing you want is to make that go away, which is why main line stoppages are a priority call here at John Moore. John Moore’s immediate solution- and one of the first things we do at any job where we’re fixing a main line stoppage- is clear the obstruction to allow your home’s waste-water to flow through the main line again.

Before we attempt to clear the stoppage, we try to identify roughly where the stoppage is occurring in your main line, either under your home, or under your yard or driveway. We do this by noting the location of each fixture that’s backing up and by opening the two-way cleanout outside of your home. If the two way cleanout is also backed up, then we know that the stoppage is somewhere past that point in the main line and can run a snake cable from there. If the two-way cleanout is not backed up, then we run our main line clean-out cable through a drain in your home.

When we run a cable in an attempt to poke a hole in the stoppage, eventually one of two things will happen: 1) We will hit the stoppage, poke through it, and then the water from your backed up drain will begin going down or 2) We will hit a tough spot indicating to us that we have either hit mud from channel rot or a root ball. If we hit a tough spot, we can usually tell if it’s mud or roots. And if it’s roots, we will use an attachment and attempt to pull some of the roots off, allowing water to drain. If it’s mud, we know we’re probably dealing with channel rot or a hole in your pipe and will recommend a reroute.

Sewer Line

Visually Inspect the Main Line by Running a Camera

After we have poked a hole through the stoppage and allowed water to start draining again, we will ask to run a camera to make a visual inspection. A visual inspection will give us a better idea of where the stoppage is occurring and what’s causing it so we can find the best solution.


Sometimes when we do a visual inspection, we find that there is a lot of grease and other build-up on the sides of the pipe. This build-up not only decreases the inside diameter of your pipe, but also makes it difficult for us to identify the actual problem, whether it be a bellied pipe, tree roots, or channel rot. So our solution if we find a lot of build up is Hydrojetting, a second cable that shoots water out at up to 4000 psi, effectively clearing out any grease, gunk, and other goop getting in our way.

Typically, after doing the above three, we will have solved the immediate backup issue and identified what caused the main line stoppage in the first place. After this, John Moore highly recommends moving forward with replacing or fixing your main line so that a stoppage won’t happen again anytime soon.


After this, John Moore highly recommends moving forward with replacing or fixing your main line so that a stoppage won’t happen again anytime soon.

Main Line Repair and Replacement

To permanently fix a main line and prevent recurring stoppages, we have to dig.

Now, whether we’re simply digging a trench or actually tunneling under your home depends on where the problem area is. For instance, if we find out during our visual inspection that the cause of your main line stoppage is tree roots, then we will dig a trench, remove the concrete pipes, replace them with schedule 40 PVC, and tie them into the city line. But if we find that the problem is a bellied PVC pipe or channel rot occurring underneath your home, then things get a little trickier.

Tunnel Repair

To fix any length of pipe under your home, we have to dig an access tunnel. Sometimes, all that’s needed is a spot repair, which is when we fix a little section of pipe. For instance, if we determine from our visual inspection that your main line stoppage is occurring right next to a fixture, like a tub or a toilet on the edge of your home, than we only have to dig a small access tunnel. But if your main line has a belly in the middle of your home, we need to dig a long access tunnel and either reslope the pipe or completely replace it. In instances where the problem is cast iron channel rot, we will replace sections or the entire main line with schedule 40 PVC.

Main Line Reroute

When we’re running a cable down your pipe to clear the stoppage, if we hit mud, we recommend a reroute. Why? Because mud indicates that there is a hole in your main line, and it’s almost impossible to patch a hole in an underground pipe. So the easiest solution is to reroute.

For a reroute, we cap the old line and build a new one running from your fixture to the outside of your home and then back underground. We either tie this rerouted line past the area that’s rotted through on your main line, or we reroute and replace the main line completely. John Moore always uses schedule 40, solid core PVC in our reroutes, and we try to use a thicker diameter pipe with steep slope to ensure your waste-water can easily flow down your main line and get where it’s going.

New Sewer Line


John Moore Licensed Technicians

Hear what our customers are saying about our employees and our service.


David Lawrence with John Moore managed the team and took care of my home during the complete repiping of my home. He treated my home with loving care, and responded to me so quickly. He recognized problems, and contacted me in regards to issues as he discovered me, and texted me every day when he arrived and when he left. He showed up on a Saturday when I was freaking out, and he took care of all the small issues that arise when you have a contractor lead.

- Plumbing Houston

Troy Watts was AMAZING to work with, very knowledgeable and professional. I asked a lot of questions and he was patient and made sure we were fully comfortable with the path forward. We had a great experience and I would highly recommend them.

- Plumbing Houston

(877) 730-2525

Or click below to schedule service online.