How Much Does a Backflow Preventer Cost in 2025?

Average Cost to Install a Backflow Preventer

Backflow Preventer Cost Factors

When determining the price of a backflow preventer, consider the type and size of the system, testing requirements, labor, permits, and additional features.

Cost by Type

Several types of backflow preventers are available, each designed for a specific appliance or plumbing system. Prices vary greatly depending on the type you choose. Garden hose backflow preventers are the most affordable, starting at $3, while floor drain options can run up to $1,000.

Garden Hose or Appliance

Backflow preventers designed for garden hoses or appliances cost between $3 and $100. Lower-cost versions, often designed to fit on the end of a garden hose, range from $3 to $35. These models keep water flowing in one direction, preventing dirt from contaminating the supply. 

Backflow preventers for appliances like power washers are slightly larger and must be installed downstream of a residential water meter. These models often cost $10 to $100. 

Sprinkler or Sewer System

Backflow preventers for sprinkler or sewer systems typically cost between $100 and $600. Larger and more complex than those for hoses and appliances, these models are installed on a main sewer pipe. Atmospheric models have several valves and chambers that allow air to enter the pipe to prevent backflow, while reduced-pressure models feature valves that block backflow when water pressure drops.

Basement and Floor Drains

Preventing backflow in harder-to-reach areas of your home—such as a basement—is often the most costly. Contractors must access buried pipes, increasing the complexity of the installation and driving up costs. These models typically range from $150 to $1,000. 

Cost by Size

Backflow preventer costs vary depending on the size of the valve needed, ranging from $35 to $600. Valves are typically measured in diameters of 0.5 to 12 inches. 

Backflow Testing

Backflow testing typically costs $70 to $90 but can be as high as $350, depending on your location. Some cities require annual testing and inspections. They may send someone to test your system for a fee or require you to hire a private company.

Labor

Labor is often the most significant cost when adding a backflow preventer. The cost to hire a plumber ranges from $180 to $500 per hour, depending on their experience and location. They can typically complete the job in one to three hours, with total labor costs ranging from $100 to $400. 

Permits

Permitting fees for backflow preventers usually cost around $50. However, the amount may vary by state and municipality. Contact your local municipality to determine if a permit is required for your project.  

Thermostatic Freeze Relief

Thermostatic freeze relief valves cost about $100 on average. In extremely cold temperatures, backflow preventers can stop working or even fracture. These valves are installed directly on exposed pipes during the winter to automatically decompress the pipeline with cold water pressure. 

Anti-Theft Device

Anti-theft devices like steel cages or locks typically cost between $200 and $300. Thieves may target backflow preventers for their copper and brass elements. They’re easier to access than indoor piping, so many homeowners choose to safeguard their systems. 

Does Installing a Backflow Preventer Increase Home Value?

Installing a backflow preventer won’t significantly increase your home value, but it can improve the safety and function of your plumbing. Potential buyers concerned about contamination risks may find your home more appealing due to the added protection. Many insurance agencies also offer discounts for installing a backflow preventer, adding the benefit of reduced home insurance costs. 

Budgeting for Installing a Backflow Preventer

Looking for ways to save on your backflow preventer? Consider the following tips to make your project more budget-friendly: 

• Compare quotes from at least three plumbers in your area to find the most cost-effective, reputable option.

• Ask contractors in your area if they offer seasonal discounts or promotions. You can often save by scheduling installation during the off-peak season.

• If you have other projects to complete, bundle the cost of multiple plumbing jobs to make the most of the labor fees.

• Check if your local municipality offers rebates or incentives for installing a backflow preventer in your home. 

• Consider whether additional features, such as anti-theft devices, are truly necessary in your area.

How HomeAdvisor Gets Its Cost Data

No place is more important than your home, which is why HomeAdvisor connects homeowners with local pros to transform their houses into homes they love. To help homeowners prepare for their next project, HomeAdvisor provides readers with accurate cost data and follows strict editorial guidelines. After a project is complete, we survey real customers about the costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from 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.