How much will your project cost? Get Estimates Now

How Much Does It Cost To Install A Backflow Preventer?

Typical Range: $135 - $1,000

Find out how much your project will cost

Cost to Install or Replace a Backflow Preventer

On average, backflow preventer installation costs about $300. Most homeowners pay between $135 and $1,000 depending on the size and type of the system. The device itself ranges from $35 to $600, while professional labor costs between $100 and $400.

Expect to pay between $70 and $250 for a backwater or check valve, including install. A single valve is easier to install than a comprehensive double-valve preventer system. Professionals can tell you whether your home needs one or the other. Both prevent backwater from flowing in, but the check valve only controls the flow while the other offers reliable stoppage. Should water come in at significant pressure, only multiple valves can stop it.

These units prevent dirty or polluted water from tainting the supply. In its simplest application, you can attach a single backwater unit to a garden hose. A preventer is perfect for sprinkler and irrigation systems as well as sewer lines. It attaches to your connection to public water supplies to prevent backflow. Failing or improperly installed units can lead to sewage backups and tainted water, which is why working with a pro is best.

Backflow Preventer Costs

Budget between $35 and $600 for the preventer system itself. Where on that range you land depends on the size and purpose of the unit.

Residential Backflow Prevention Devices by Size

Most residential products fit 3/4-inch pipes, but the size of the valves will change the price.

Common Sizes & Prices of Backwater Prevention Systems




$35 - $55


$50 - $100


$75 - $200


$100 - $300


$150 - $400


$400 - $600

Sewer and Sprinkler Check Valve Backflow Systems

Valve systems, usable for both sewers and sprinklers, cost between $200 and $600. They are essentially identical and can be used interchangeably. Both consist of a series of gates and chambers that sit directly on the backlogged water or sewage pipe.

Get a Quote From a Plumber for your Backflow Preventer
Return to Top

Backflow Preventer Installation Costs

The rate for professional installation ranges between $100 and $400. Placing the preventer in the pipe during initial construction is between $100 and $250. Having to retrofit an existing pipe ranges between $150 and $400. Whether or not you work with a pro, you might have to pay up to $50 for a permit in addition to that price.

Backflow Preventer Replacement Costs

Backwater prevention replacement requires cutting open the pipe which adds $50 to $150 in labor. That brings total replacement cost to $150 to $400 for the work alone.

Sewer Backflow Preventer Installation

Installation costs $200 to $400 because most sewage backflow systems include multiple valves. It's typically installed at the main sewer line leading to your home or in your basement at the furthest exit point from the home. The homeowner, not the city, is responsible for installing and maintaining the system.

Install or Replace Sprinkler Backflow Preventer

To prevent backwater in your sprinkler, expect to pay between $100 and $400 for system installation. This cost is typically included in the price to install a new sprinkler system. Only adding a new valve to an existing unit or replacing it will require you to budget additional funds.

Compare Rate From Different Plumbers
Return to Top

Backwater Valve Costs

Simpler backwater prevention systems consist of a single valve with a price between $70 and $250 for parts and labor. They're best for garden hoses or power washers. They can stop backwater flow enough to prevent immediate issues, but reliability is low, and the danger of failure is high.

Unlike more comprehensive systems, single valves live downstream from the residential water meter. They cannot fully prevent flooding in your basement or home as they don’t block water in both directions. They cost less and are easier to install that larger systems but can only work for simple drains. 

Basement & Floor Drain Valves

Typical costs for a basement valve range from $150 to $250 including installation. Most models attach to 2, 3 or 4-inch drains. They prevent your basement floor drain from backing up. If the drain is difficult to access or the pipe is buried in cement, costs can be as high as $1,000.

Backwater Valve Installation Costs

A simple backwater valve can be as little as $50 or as much as $150. They connect to 3/4-inch hoses and pipes and are no longer than 2 inches. Installation tends to be simpler and ranges between $20 and $100. This is the type of valve that’s inserted into the end of an interior water pipe or garden hose. 

Valve Replacement & Repair

You can get professional replacement of a single valve for $150 to $500. That includes removing the existing unit, purchasing a new one, and installing it.

Not all breakdowns require replacement. If the failure is minor, an expert will be able to repair it for $50 to $150.

Talk to a Pro to Install A Backwater Valve
Return to Top

Backflow Testing Cost

Testing the flow of backwater costs between $20 and $100. This procedure ensures that your prevention system or single valve blocks the backflow.

Only some municipalities require annual testing, but it's always recommended on an annual basis to prevent breakdowns. Some, but not all plumbers, offer this service. They typically take no longer than an hour and work directly at the unit.


What is a Backflow Preventer?

A backflow preventer is a combination of valves that prevent dirty and potentially hazardous liquids from flowing into your house or property through its drains. It commonly connects to sewage pipes and sprinkler systems.

What is a Backwater Valve?

A single backwater valve shuts itself when water attempts to flow upstream on and into your property. That keeps the water in the system clean. Common applications are in basement drains, garden houses, and other simple piping systems.

What Do Backflow Repairs Cost?

Backflow repair costs range between $50 and $150plus any cost of parts. Repair is possible if a single valve or part fails. If it breaks down further, you might need complete replacement at a rate between $150 and $500.

Are Backflow Valves Required on Residential Properties?

Not all municipalities require backflow valves on residential properties. Check with your local authority. You might need a permit for installation, which costs between $0 and $50 depending on location.

What is a Floor Drain Backflow Preventer?

A floor drain backflow preventer is a device that seals the drain if water in the drain pipe rises to a certain level. It automatically reopens when the water flows away. You'll most likely find it in basements. It typically works using a rubber float that triggers when the water level rises, preventing it from entering the basement.

Do I Need a Sewer Ejector Pump Installed with my Valve?

Not all backwater valves need sewage ejector pumps. This system pumps sewage away from the property if the drain is below the main sewer line. It's valuable to prevent backups, making it useful for basements that might also need backflow preventers. Combining the two is possible. Whether you should do it depends on your situation.

DIY vs. Hiring a Plumber

Homeowners with plumbing and piping experience can install simple drain valves. More complex systems with multiple valves require professional help. An expert can tell you exactly what type of preventer you need, how big it should be, and add it without leaks. The project usually starts with a quick evaluation to determine your needs before labor begins.

Most plumbers are familiar with these prevention systems. They can also help you get a permit if necessary, and regularly test the unit to make sure it still works. Find a plumber with the expertise to help keep your water clean and home dry.

Hire a Plumber for Backflow Preventer Installation
Return to Top
Was this page helpful?

Was this page helpful?

How could this page be more helpful?

How do we get this data?

  1. Homeowners visit to find a top-rated pro to complete their home improvement project or repair.

  2. Once their projects are completed, the members log in to their accounts and complete a short cost survey.

  3. After compiling and organizing the data, we report it back to you.