How Much Does a Sewer Backflow Preventer Cost?

Ben Kissam
Written by Ben Kissam
Updated January 18, 2022
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Sewer backflow preventers start at around $300 for parts and installation—although you might wind up paying quite a bit more if your pipes are under your basement

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On average, it costs around $300 to install a sewer backflow preventer in your home. However, you could wind up paying between $600 and $800 (or more) if extensive labor is required due to labor costs. The parts necessary to complete the job yourself cost as little as $100. But the complexity of your home’s layout and the type of device your plumbing system needs could drive up the costs.

How Much Does Sewer Backflow Preventer Installation Cost?

This sewer backflow preventer cost guide will break down how much you can expect to pay for each aspect of the project so you can make the right choice for your budget and home goals.

There are three main costs associated with installing a sewer backflow preventer:

  • Parts: $35-$65 (can be up to $200, depending on where you live)

  • Labor/Installation: $150-$450+

  • Permit: $50

Keep in mind that these costs refer to residential sewer drains, not commercial properties, which could require a more extensive installation. Those projects typically cost more.

What Factors Influence the Cost of Sewer Backflow Preventer Installation?

Backflow repair costs can vary quite a bit, especially if you need to dig into your foundation to access your plumbing.

When considering sewer backflow preventer installation cost, you should:

  • Determine the type of device you wish to install

  • Determine the size of backflow preventer you need (they range from one-half to 12 inches)

  • Know whether you’re installing a new sewer backflow or retrofitting an existing one

  • Know how to gain access to your plumbing pipes (i.e., in your basement or outside)*

  • Assess the general complexity of the job

*If your pipes are below the basement, you may have to drill into the floor, which can up the price significantly.

How Much Does It Cost to Install a Sewer Backflow Preventer Near You?

The national average cost for installing a sewer backflow preventer is about $300 for parts and labor. Although larger device installations and high cost of living areas could bring the price to as much as $800 for parts and labor.

Whether you go it alone or hire a pro, you’ll also need to pay a permit fee to your town’s sewer service, which starts at $50. This fee can go even higher if you’re installing a backflow preventer in a commercial property or as part of a larger sprinkler system.

What Sewer Backflow Preventer Can I Get on My Budget?

Most sewer backflow preventers are made out of PVC pipe. But additional features can drive your costs up. 

Here are some backflow preventer cost guidelines for your installation:

  • Most affordable: Basic PVC pipe (starting at $35)

  • More expensive: PVC pipe with extendable top ($75-$150)

  • Most expensive: PVC pipe with clear plastic lid and/or other features ($150-$200)

You may also be able to save a few dollars by getting a basic PVC pipe model. Clear backflow preventers or ones with removable tops tend to be a little more expensive.

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How Much Does It Cost to Install Sewer Backflow Preventer by Type?

The cost of installation won’t change much based on the type of sewer backflow preventer you choose (i.e. PVC pipe vs. clear or removable tops). Most of your expenses will come from the labor hours of installing the device. 

While some backwater valve installation costs are cheaper than others, the distance between your home and the neighborhood’s main sewage line can help you decide which type of device you should install. 

The further away, the more costly future repairs could be, so going with a more expensive option is a smart investment. Hiring a plumber can be helpful, or you might simply ask a plumber who knows your area for advice on what you’ll need for sewer backwater valve installation.

How Much Does It Cost to Install a Sewer Backflow Preventer Yourself?

You can install a sewer backflow preventer by yourself for as little as $35 if you have the tools necessary to get the job done. However, the layout of your home could drive the price up. 

For example, you may need to rent or buy a drill to access the area underneath your basement floor. In older houses, you may need to remove objects that block the spot where you will have your backflow preventer installed.


What should I consider when installing a sewer backflow preventer?

Be sure to consider how often you may need access to your pipes in the future. This can help you decide if you want to install a basic PVC backflow preventer or spring for a clear or removable one. 

If you think you’ll need access to your plumbing often, or if your pipes have a history of problems, it’s probably worth spending a little more for something you can look into without removing the backwater preventer.

What other projects should I do at the same time?

If you’ll be digging up your floor to get access to your pipes when putting in a sewer backflow preventer, this would also be a good time to take care of any other plumbing issues or renovations.

For example, you could also put in additional pipes if you wanted a bathroom in your basement. Since the floor will be sealed over with concrete when you’re done, now’s a good time to take care of those bigger tasks.

Should you hire a pro for sewer backwater installation?

For complex projects that involve drilling, hiring a professional plumber makes a lot of sense. You’ll pay a couple hundred dollars extra, but you’ll also have peace of mind that a pro will handle the job. If you can easily access your pipes in your front or backyard, DIY installation is definitely a great way to save money.

Either way, installing a backflow sewer preventer is great for your plumbing and your family’s health, as it’ll keep smelly water from backing up in your pipes and infiltrating your home.

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