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How Much Does It Cost To Install A Backflow Preventer?

Typical Range: $135 - $1,000

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November 18, 2021

Installing or replacing a backflow preventer costs $300 for the average homeowner. However, actual project costs fall somewhere between $135 and $1,000 based on the system sizes and styles you choose. The cost for bringing a new backflow preventer into your home is divided between the price for the unit and labor costs.

On This Page:

  1. Average Cost to Install a Backflow Preventer
  2. Backflow Preventer Prices
  3. Backflow Preventer Installation Costs
  4. Backflow Preventer Installation Cost by Type
    1. Sewer
    2. Sprinkler Systems
    3. Basement and Floor Drains
  5. Backwater Preventer Valve Pipe-Size Cost Factors
  6. Cost to Install a Backwater Preventer Yourself
  7. DIY vs. Hire a Backwater Preventer Pro
  8. FAQs
    1. Should I try to install my own backflow preventer?
    2. Do I need a permit to install a backflow preventer?

Average Cost to Install a Backflow Preventer

Low cost$135
Average cost$300
High cost$1,000

Backflow Preventer Prices

The average backflow preventer installation cost around the country is $300. However, you can expect to find yourself getting a bill from as low as $135 to as high as $1,000. The biggest price associated with installing your new backflow preventer is the unit itself.

Available in a range of different models, backflow preventers are priced from $35 to $600.

Backflow Preventer Installation Costs

Installation represents a big chunk of your bill when adding a backflow preventer. Labor costs for this job fall between $100 and $400.

If you need existing piping retrofitted, the labor can cost between $150 and $400. If your town or county requires a permit for this project, factor in at least another $50 in permit fees.

Backflow Preventer Installation Cost by Type

Project costs vary based on complexity and location. Take a look at average prices based on the nature of where in your home or property you're controlling the flow.


Requiring multiple valves in most cases, sewer backflow preventer installation typically costs between $200 and $300. That estimate figures in the cost for extra labor time and valves. When placing a backflow preventer for sewer protection, the installation typically occurs at the main sewer line. It can also be placed in the portion of your basement that represents the furthest exit point in your layout.

Sprinkler Systems

If you're trying to stop sprinkler backwater, expect to pay $100 to $400 in sprinkler system repair costs.

Basement and Floor Drains

If you're preventing backflow in your home, the cost to get this project done in your basement ranges from $150 to $250. However, the price can increase significantly if your drain is difficult to reach.

Buried pipes can also increase project costs for a basement backflow preventer. Some homeowners find themselves paying as much as $1,000 for backflow preventers in basement floor drains.

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Backwater Preventer Valve Pipe-Size Cost Factors

Pipe size can scale up project costs. Standard backwater valves will connect to 3/4-inch hoses and pipes that aren't any longer than 2 inches. A standard basement valve will attach to drains that are 2 inches, 3 inches, or 4 inches. Ordering a non-standard size could cost more.

Cost to Install a Backwater Preventer Yourself

The biggest cost of installing your own backwater preventer is the device itself. Costs for materials can go as low as $35 for a valve-only solution to as high as $600 for a sophisticated system.

DIY vs. Hire a Backwater Preventer Pro

If you have some plumbing experience, installing a drain valve to prevent backwater shouldn't be difficult. However, the complexity level skyrockets if you're installing a more sophisticated system.

To turn this into a DIY project, you have to be confident that you know how to select the right system or valve for the size and style of your pipes or drains. You also have to be confident that you can retrofit piping if it turns out your system can't fit a backwater preventer as-is. If you can't be certain you can create a leak-free installation, consulting a local plumbing pro is the best option.

Plumbers know how to fit the right backwater preventer to the unique piping of different homes. What's more, they have the expertise to provide a leak-free installation that won't leave you worried about moisture, mold, or flooding issues. Ease your mind by bringing in a pro for a backwater preventer inspection if you suspect you need a repair, replacement, or installation.


Should I try to install my own backflow preventer?

This DIY option isn't out of the question if you understand your home's piping. However, the general affordability of a professional backwater preventer installation makes hiring a licensed plumber the better option for most.

Do I need a permit to install a backflow preventer?

The answer varies by town and municipality. Always ensure that you're looking up local permit requirements before beginning this project on your own. You could be on the hook for repair costs if your home experiences leaking due to a faulty backflow preventer DIY installation. If you bring in a local plumber to help with the job, you can rest assured that they will already be familiar with all of the local permit requirements for this project. Most plumbers pull permits for their clients prior to beginning work.

What does a backwater preventer do?

A backwater preventer can play an important role in keeping your house safe and stable! There are actually several reasons why you might need one at your property based on location and topography. A backflow preventer is a valve system that stops the water in your main water supply from creating a reverse flow in the wrong direction. Once in place, a backwater preventer will ensure that clean, sanitary water gets to your pipes. This will keep all of your drinking water, bathing water and home-use water clean.

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