Backflow Preventer Cost

• A small backflow preventer that threads onto the end of a garden hose to stop dirt or fertilizer from entering the water supply typically costs $3 -$35. These are simple devices that allow liquid to only flow in one direction. For example, the T&S Brass B-0972 Atmospheric Back Flow Preventer with a 3/4" hose fitting costs $21 -$31.
• Slightly larger backflow preventers prevent backflow on hoses to appliances like a boiler or on equipment like a power washer typically cost $10 -$100. For example, the Watts Bronze #7 3/4" Backflow Preventer costs $48 -$54, and is designed to be installed downstream of a residential water meter.
• Backflow preventers designed to be installed with a residential sprinkler/irrigation or sewer system are larger and more complex than those for hoses, and typically cost $100 -$600 or more. These backflow preventers are usually a single unit containing a series of valves and chambers and installed on a main water or sewer pipe. Residential backflow preventers are typically atmospheric (allowing air to enter the pipe so a siphon effect cannot occur) or reduced-pressure (with valves that mechanically block backflow when the pressure drops). For example, the Apollo 40204T2 Backflow preventer 3/4" in bronze, $250 -$495, is a reduced-pressure backflow preventer.
• Professional installation of a residential backflow preventer can cost $25 -$250 depending on location and complexity. Installation of a backflow preventer is often included in the total cost of installing a sprinkler system.
• Non-residential backflow preventers for small commercial or multi-family buildings can cost $1,000 -$10,000 or more depending on size and type. Installation costs vary depending on size and location. The New York City Environmental Protection Department estimates complete installation of an approved backflow prevention device can cost $3,000 -$5,000 on a small one-story building; $3,750 -$5,500 on a small two-story structure; and $5,000 -$7,000 for a mid-sized building like a car wash, laundry or small manufacturing facility. The city of Augusta, GA, estimates that installing an industrial backflow preventer can cost $30,000 or more, depending on the size of the device.

• If a water main bursts, pipes freeze or there is unexpectedly high demand on the system, the pressure in the water pipe drops and can create a siphon effect, drawing contaminated water from the ground, storage or from other sources. A typical residential backflow preventer stops this from happening by creating a barrier to prevent water from flowing back up a pipeline. The RainBird Corp. provides a video overview of backflow preventers for home sprinkler/irrigations systems.
• Local health and building codes can dictate the type of backflow preventer required, how deep to install the pipe, the dimensions of the backflow preventer box and the limits of installation. Check with local government officials before installing a backflow preventer.
• Small backflow preventers on hoses are simply screwed into place. For larger backflow preventers on water or sewer lines, the water supply must be turned off, the pipe cut and the backflow preventer installed. Some simple backflow preventers can be installed by do-it-yourselfers with standard plumbing skills, but in many areas a backflow preventer on a sewer or irrigation system must be installed by a licensed plumber. LandscapingUniversity.com provides a video demonstrating backflow preventer installation.

• There may be a nominal permit fee (free to $50) for installing a backflow preventer; check with city or county officials.
• Many areas require a backflow preventer to be inspected and tested each year, and testing costs vary depending on location and who is doing the testing. For example, Paradise Irrigation District in Northern California charges $40 to do an annual test, while the city of Boulder, CO, does not perform the test and estimates that private companies charge $25 -$350.

• Contact the local sanitary district for advice and assistance, and to learn what type of backflow preventer should be used. Search for a sprinkler/irrigation specialist through the Irrigation Association or for a local licensed plumbing contractor through the Plumbing-Heating-Cooling Contractors Association.
• If a backflow preventer is optional under local regulations, sewersmart.org explains how to determine if a home is at risk of a sewer backup.

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