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How Much Does Sewer Backflow Preventer Installation Cost? [2026 Data]
Normal Range: $150 - $450
The average cost of sewer backflow preventer installation is $150 to $450, with a national average of $350. Budget for annual backflow testing and maintenance.
How we get this data
Photo: Kathrin Ziegler / DigitalVision / Getty Images
Photo: Kathrin Ziegler / DigitalVision / Getty Images
Highlights
The type of backflow preventer and where you install it are the most impactful cost factors.
Installing a main-line backflow preventer is the most expensive option, but it can satisfy local requirements and cost less than installing individual preventers throughout your plumbing system.
For exterior backflow preventers, be sure to budget for weatherproofing to prevent freezing in colder climates.
Budget for routine backflow preventer testing to ensure ongoing functionality and avoid surprise costs down the road.
Backflow preventer installation costs between $135 and $1,100 (or more if extensive labor is required). On average, you’ll pay $350 to install a backflow preventer. The complexity of your home’s layout and the exact device your plumbing system needs could drive up the costs.
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 costs, you should think about the following factors.
Preventer Location
When it comes to safeguarding your water supply from potential contamination, choosing the right backflow preventer is crucial. These devices come in various sizes and types, each tailored to specific applications. Here's a cost breakdown to help you make an informed decision.
| Type of Preventer | Average Cost* |
|---|---|
| Hose | $3–$35 |
| Appliance | $10–$100 |
| Sprinkler/sewer | $100–$600 |
| Basement drain | $150–$1,000 |
*not including labor
From one homeowner to another
I had another company design my septic system replacement, but Paul re-designed it to avoid having to remove a 50+ ft tall tree and added a drainage system for the water from the gutters. The old no-longer-up-to-code 2-cesspool septic system was replaced by a drainfield and Ecoflow septic tank. The work was done on the days I was told workers would be here (unlike the company that drew up the first set of specs), and Paul and Jon were always friendly and great to work with.
Review of PR Environmental Designs, Inc., in Chester Springs, PA
Type of Preventer
Though labor makes up the majority of the cost for this project, the preventer type also has a small impact.
| Preventer Type | Average Cost |
|---|---|
| Basic PVC pipe | $35–$150 |
| Extendable top | $75–$150 |
| Clear plastic lid | $150–$200 |
Valve Size
The cost of a backflow prevention device varies widely, often ranging from $35 to $600. Factors like system size and desired efficiency greatly affect the price. If you're installing multiple units, you might see some cost savings, including reduced labor expenses.
| Valve Diameter in Inches | Average Cost* |
|---|---|
| 1/2 | $35–$55 |
| 1 | $50–$100 |
| 2 | $75–$200 |
| 6 | $100–$300 |
*not including labor
Condition of Pipes
However, when dealing with older pipes made from non-plastic materials, the installation process can become more complex and expensive. Retrofitting such pipes for backflow prevention requires specialized techniques and materials, raising the overall project cost. Careful consideration of these factors is essential for informed decision-making.
Job Complexity
The cost of your backflow prevention system depends on factors like system size and type. Pipe system age is a significant factor, as older systems require more complex installation, increasing costs. Larger houses also necessitate more robust preventers, further impacting the overall price.
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 $350 for parts and labor. However, larger device installations and high cost of living areas could bring the price to as much as $1,100 for parts and labor.
Local Permitting Fees
Whether you go it alone or hire a pro, you need to pay a permit fee to your local 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:
| Preventer Pipe | Average Cost |
|---|---|
| Basic PVC pipe | $35+ |
| Extendable top | $75–$150 |
| Clear plastic lid | $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.
Why You Should Hire a Sewer Backflow Preventer Pro
Hiring a sewer backflow preventer pro near you will add around $35 to $200 to your project in labor costs. This extra cost, however, will make a huge difference in the success of the installation.
Here’s why it’s ideal to hire a sewer backflow preventer pro
Installing a sewer backflow preventer requires serious experience and knowledge, so here’s why you should hire a pro:
Professionals can acquire the correct permits and comply with building codes and zoning regulations.
Complex layouts can make installing a sewer backflow challenging.
Pros have the skills and equipment to correctly install a sewer backflow preventer.
Pros understand the best way to install a backflow preventer and may recommend winterization upgrades or anti-theft mechanisms, depending on where you live.
Trying to DIY this project can lead to contaminated drinking water, safety issues, grey water damage, and costly repairs later on from a faulty installation.
Your pro may offer you a deal on future annual backflow testing.
The best, most trusted installers carry insurance and offer labor warranties and guarantees.
If you want to DIY a sewer backflow preventer
If you want to play an active role in the sewer backflow preventer installation process, consider smaller tasks like the following:
Removing objects that may slow down the installation
Maximizing accessibility by clearing any obstructions or obstacles
Acquiring the permit ahead of time
Cost of Common Add-Ons
When planning a backflow preventer installation, it's essential to consider additional components that can enhance functionality and security. Here are some common add-ons and their estimated prices:
Thermostatic Freeze Relief
To protect your backflow preventer from freezing during cold weather, buy a thermostatic freeze relief valve. Prices vary depending on the type and size of the valve but often cost around $100.
Anti-Theft Device
Prevent theft and tampering of your backflow preventer by adding an anti-theft device. These can cost anywhere from $200 to $300, depending on the model and security features.
Ongoing Costs
Beyond the initial installation, understanding the ongoing costs associated with maintaining and ensuring the effectiveness of your backflow prevention system is crucial for long-term reliability.
Backflow Testing
Regular backflow testing is crucial to ensure the preventer functions correctly. Testing costs vary depending on location and service providers but typically range from $70 to $90 per test. Annual testing is often recommended to maintain compliance with local regulations.
Repairs to an Existing System
If your existing backflow preventer requires repairs, the cost can vary widely based on the extent of the damage and the specific parts needing replacement. Repairs can cost anywhere from $50 to $100, depending on whether the fixes are minor or are complete overhauls or component replacements. It's essential to address issues promptly to maintain the system's integrity and compliance.
How to Save Money on Backflow Preventer Installation Costs
Saving on backflow preventer installation costs can be achieved through several strategies:
Compare quotes from multiple reputable contractors to ensure you're getting a competitive price.
Consider installing a basic PVC pipe backflow preventer for simpler applications, as they are cost-effective and have minimal installation requirements.
Bundle multiple plumbing jobs if you have other projects you need to complete, which may lead to discounted labor costs.
Regular septic tank maintenance and testing can also reduce long-term expenses by preventing costly repairs or replacements.
Check for local rebates or incentives for backflow prevention installation to further reduce your upfront costs.
Next Steps: Finalize Your Project With a Pro
Be ready to discuss the type of preventer you want with your pro, including a hose, appliance, sprinkler, sewer, or basement drain type of system.
Depending on the type of water system, the best backflow preventer will vary, so map out any irrigation systems, swimming pools, and wells on your property ahead of time.
Consider the materials you want to use, like a basic PVC pipe, an extendable top, or a clear plastic lid.
Decide whether you want to invest in upgrades like a thermostatic freeze relief valve or an anti-theft device.
Though your professional backflow preventer pro can help you figure out the correct measurements for your device, it’s a good idea to measure your yard yourself and get an idea of what valve size you need.
How Angi Gets Its Cost Data
Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We extensively research project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We rely on reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects.
Want to help us improve our cost data? Send us a recent project quote to [email protected]. Quotes and personal information will not be shared publicly.
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