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CostHelper > Home and Garden  > Plumbing & Waterproofing > Backflow Preventer

Backflow Preventer Cost

How Much Does a Backflow Preventer Cost?

low costInstalled on Garden Hose or Appliance: $3-$100average costInstalled With Sprinkler, Irrigation or Sewer System: $100-$600+high costCommercial or Multi-Family Backflow Preventer: $1,000-$10,000+
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A backflow preventer stops water from flowing back up a hose or pipe, preventing dirty or polluted water from tainting public drinking water supplies. Backflow preventers are typically required with any new sprinkler/irrigation system, and a backflow preventer on a home's sewer line allows any backed-up water or other materials to escape a clogged line through a valve instead of flowing into the home. Small backflow preventers may also be installed on a hose leading to a hot water heater or other water-based appliance.

Typical costs:

  • 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[1] 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[2] 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[3] 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[4] , estimates that installing an industrial backflow preventer can cost $30,000 or more, depending on the size of the device.
Related articles: Sprinkler System, Drip Irrigation, Replacing a Water Heater

What should be included:
  • 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[5] 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. provides a video[6] demonstrating backflow preventer installation.
Additional costs:
  • 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.
Shopping for a backflow preventer:
  • 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[7] or for a local licensed plumbing contractor through the Plumbing-Heating-Cooling Contractors Association[8] .
  • If a backflow preventer is optional under local regulations, explains how to determine[9] if a home is at risk of a sewer backup.
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What People Are Paying - Recent Comments
Backflow preventors - RPBA for domestic or DCDA for larger units
Amount: $1.00
Posted by: jdeepinit in Buckley, WA.Posted: February 19th, 2015 02:02PM
Size: 1/2" to 2"Brand: Watts
Type of Installation: com or res
I am in installer of cross connection control devices with in the Washington State area. Most backflows that are on the CCC list of approved devices will cost you anywhere from $100 to $300 just for the backflow unit. You you begin to add the small parts, truck and tools and then add the labor.. the total cost of this T&M should be making me at least half a days wage, or it's not worth my time to install. These are now a Federal requirement, But don't expect to be "over charged" - For small units w/o much time/labor/ material -$500 + permits / testing sounds like a good deal. One of our local Cities charges $475.00 just for the permit to install one. And for the 2 install in NY for $7500 - I may have flown out / installed these / toured the city and came home with a few hundred in my pocket.
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The truth about Backflow preventers
Amount: $7,500.00
Posted by: marcoe in nyc, NY.Posted: January 7th, 2015 12:01PM
Size: 1/2 and 3/4Brand: Watts
Type of Installation: mixed com/res
My Backflow preventer reduced water pressure by more than 20% on the first floor and 23% on the second. NYC requires an engineer to draw and diagram the plan for installation. NYC DEP requires annual inspection by a State certified Backflow inspector and just to make it really expensive they require the inspector to be a Licensed plumber or work for one. A certified inspector gets 60 dollars in Yonkers a Licensed plumber in the NYC 200.00. Just to inspect a check valve in a pipe. The risk of contamination is so small it does not justify the cost, but then again DEP does not care you are paying.
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1/2" back flow preventor
Amount: $525.00
Posted by: Tray47 in Mesa, AZ.Posted: June 26th, 2013 03:06PM
Size: 1/2"Brand: Prwbh00090
Just had a back flow installed, other work included; copper male adapter, PVC adapter, PVC 90 degree joint, 1/2" coupler, 14" PVC pipe. Does sound more then I should have paid. Valve is in the open, no bushes, etc in the way. Would appreciate feedback
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