Install Sewer Backflow Valves


Make Resilient Upgrades | Strengthen Your Home • Floods | Hurricanes

Why do they matter?

When you think about flooding, you probably think about water coming in from outside your home. But during flood events, floodwater can also enter your home through the wastewater plumbing system designed to carry sewage out of your home. When flooding occurs, sewage systems can be overwhelmed, pushing sewage from sanitary sewer lines to back up through drain pipes. These backups cause damage and create health hazards.

What do I need to know?

Backflow valves can block the flow of sewage backup. Consider the following when installing backflow valves:

  • Installing a backflow preventer valve and system is an affordable way to prevent expensive damage inside your home. Professional installation can cost as little as $135 for a simple system.
  • Valves have different complexities, tightness of the seals, and ease of use.
  • Gate valves are usually complex and require hand operation, whereas flap or check valves are simple and allow flow out and close automatically when the flow reverses. Note that flap or check valves are not as tight as gate valves, and require periodic testing. Many municipalities require annual testing.
  • Other valves combine gate and flap valves into one design.
  • All pipes that run from your home or that are connected to equipment or appliances below potential flood levels need valves. This includes washing machine drain lines, laundry sinks, fuel oil lines, rain downspouts, sump pumps, and sewer/septic connections.

Where Do I Start?

  • Contact a licensed plumber to determine the best method for your plumbing system. Ensure you schedule an annual checkup to ensure your backflow preventer system works when you need it most.

More Resources:



Protect your home

Upgrade your home for harsh weather with retrofits specific to the age and location of your house.

Please enter a valid address.

Prepare for disasters

See how to make a plan for what to do before, during and after.