How to Replace a Hose Backflow Preventer

What You'll Need
New Backflow Preventer
Vise Grip or Wrench
Thread Sealant
Tack Cloth

A hose backflow preventer is a device fitted to one end of a hose to restrict the reverse flow of water back to the water supply. When water pressure drops or reaches zero, atmospheric pressure may push the water on the hose back to the water source. This may contaminate the clean water with chemicals such as those found in fertilizers and pesticides. To prevent this from happening, backflow devices are required to be installed on every hose or pipe used for outdoor or even indoor use. Sometimes, the backflow preventer connected to a hose may lose its efficiency after long and heavy use. Here’s how to replace the old one with a new backflow device.

Step 1 – Purchase a New Backflow Preventer

Sprinkler systems require the installation of backflow devices, even if the connections make use of hoses. Hose sprinkler nozzles connected to one end of a hose still have a good chance of being contaminated with hazardous chemicals and so require backflow devices. Go to a home improvement store and purchase a new set of backflow device. Make certain to choose the correct size that will fit the hose. If unsure, bring the hose coupling to the store to compare.

Devices can be made of brass, stainless steel, or plastic. Some are equipped with timers and pressure indicators. A simple backflow device will work just fine as long as it works efficiently.

Step 2 – Remove the Old Backflow Preventer

Shut down the water supply first before proceeding. The backflow preventer may have been secured to the plumbing using tape sealant or pipe dope and may be difficult to remove by hand. Use a vise grip or a wrench to carefully loosen the connection and detach the device from the hose. Remove any debris of thread sealant from the hose threads. Use a tack cloth to wipe the threads clean. Also clean the water supply pipe.

Step 3 – Attach the New Backflow Preventer

Before connecting the backflow device to the hose, secure it first to the water supply pipe. Apply a sufficient amount of thread sealant on the device and connect it to the pipe. Hand-tighten the backflow device first and use a vise grip or a wrench to secure it firmly onto the pipe. Connect the hose to the device by following the instructions of the manufacturer.

Step 4 – Test the Connection

After installation, turn on the water supply and the hose to check for leaks. Allow the water to run for a few minutes to remove any debris left on the hose and the connection. When the water is turned off, the device may seem to leak for some time, but that is normal. It is only allowing the water to drain without allowing it to enter back into the water supply. However, if the leak does not stop, there is something is wrong with the device.