How Deep Are Sewer Lines Buried? (Find Out Now!)

Alex Praytor
by Alex Praytor

Sewer line repairs and replacement can be among the most expensive repairs you will face as a homeowner. They can set you back thousands of dollars. If you are looking into trying your hand at some of the trench work, you can cut a few corners off the bill. One of the first things you will want to know is how deep the sewer line will need to be buried.

In many areas, private sewer lines should be buried a minimum of 18 inches deep, while public sewer mains have a minimum depth of 12 feet. In geographical areas with colder climates, private lines may need to be buried several feet under the ground to avoid frozen pipes. Many states will regulate how deep or shallow your sewer line should be.

Here are some tips on how deep your sewer line should be and what steps to follow to dig the trench.

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What is the Best Depth for a Sewer Line?

According to the American Society of Civil Engineers, the depth of your sewer line will depend on many factors. These can include:

  • Soil type
  • Water table
  • Pipe material
  • Pipe diameter
  • Local regulations

How deep your current sewer line is can be a good indicator of how deep you should run a new line. Still, regulations could have changed since your last pipe was installed. In this situation, it is best to check the current regulations for the appropriate pipe depth before you start digging a trench.

Safety Measures When Digging a Sewer Line

There are a few safety factors to keep in mind if you are planning to do some of your sewer line’s trench work yourself. OSHA regulations will require you to use trench shields if your trench will be 5 feet deep or deeper. The trench shields can prevent the walls from collapsing in on you while you are at work.

While the job is in progress, you will want to cover the trench if you are leaving it unsupervised. This will prevent children or animals from becoming stuck in your trench.

Before You Dig a Trench

Before you start digging a trench, you will want to discuss your options with a professional. If just a small amount of your sewer line is damaged, you may not need to unearth your pipe to fix it. A sewer scope inspection is a minimally invasive way to check the status and stability of your pipe without having to dig it up.

Steps to Dig a Sewer Line

Whether you are hiring the job done or set on a DIY job, here is a bit of the process that goes into digging a sewer line:

Step 1: Apply for a permit

Before you invest your time and effort into digging a trench for your sewer line, you will first want to know if you are allowed to do it yourself. In some areas, this may be the job of a professional. It would be a shame to put in the work and then find out that the work has to be redone or you end up with a fine on your hands. The best way to find out if you need a permit for the job is to contact the Building Department in your area and ask.

Step 2: Follow depth regulations for your area

If you get the go-ahead from your permit officer to do the work yourself, make sure you follow the regulations in your area for how deep the sewer line should be in your area.

Step 3: Locate your sewer line

You can find exactly where your sewer line is by using an Electromagnetic Cable Locator. This piece of equipment induces a signal on a pipe or cable line. The technician should be able to locate the pipe with the receiver. Then, you can paint a line over your sewer line so you know exactly where to dig.

You can also call 811 which is the national call-before-you-dig number to find where your utilities are located. They can mark your utility lines with flags so you know where to dig and where not to.

Step 4: Dig your trench

When you start digging, you will want to go carefully as you get a sense of how deep your line is. You don’t want to cause a break in your sewer line at this step of the repair job. To start off, you will want to dig straight down, and then clear around the sides as well.

Step 5: Remove obstructions

You will want to remove obstructions as you go. This may mean you will need a chainsaw on hand to clear away tree roots, or a sledgehammer or jackhammer for concrete obstructions.

Step 6: Worksite inspection

After you are done with digging, an inspector will come out to make sure the work is done to code. They will check to make sure the trench is the proper depth and that it follows other protocols.

The digging part will require some grunt work and strategy. However, unless you are a professional plumber, it is wise to leave the installation of the pipes to the professionals. In some areas, it could even be illegal to do the plumbing work without a license. With a professional on the job, you can be sure the job is up to code. This can also prevent costly issues down the road.

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Related Questions

Where does the sewer line become the City’s responsibility?

The main underground sewer pipe is the property of the City, which carries away wastewater to be treated. Generally speaking, any sewer line on a homeowner’s property is the homeowner’s responsibility. If the issue is on a private line, the homeowner will be responsible for the maintenance and repairs. Also, the “lower lateral” portion of the pipe, which may extend off the homeowner’s property, is usually the homeowner’s responsibility.

What are common problems with sewer lines?

Sewer line problems could be the result of a “bellied pipe,” a bad installation job, or tree roots, among others. If you notice that your toilet is slow to flush or smell foul odors coming from your drains, it could indicate a problem in your sewer line.

How much do sewer line repairs cost?

Repairing a sewer line can cost anywhere from $4,000 to $25,000. This price will depend on the groundwork needed, the materials used, and the condition of your pipe.

Alex Praytor
Alex Praytor

Alex Praytor is a native Texan who got her degree in English Literature and decided to travel the globe. She finds the architecture and design of homes across cultures fascinating. In her spare time, she visits coffee shops with her family and creates projects for their own home. Alex enjoys sharing tips on how to keep repairs up to date while turning a house into a home.

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