Silence a Noisy Check Valve

Special check valves reduce pipe noise

Sump pumps and sewage ejector pumps rely on check valves to stop backflow, but they can be noisy when they slam close. Quieter alternatives are available to solve the problem.

By the DIY experts of The Family Handyman Magazine

Replacing a check valve

Waste lines from a sewage ejector or sump pump use a check valve to stop wastewater from flowing back into the basin. When these valves shut, they can make a thud loud enough to be heard throughout the house.

To quiet them, replace the old check valve with a “silent” or “soft close” check valve.

Remove the section of waste line under the check valve, disconnecting it at the union or coupling above the basin—or cutting the pipe.

Drain the water above the check valve, then loosen the clamps and remove it (Photo 1). If you don't have a shutoff valve above the check valve, install a “full port” shutoff valve on the waste line above the check valve. You won't get soaked with dirty water the next time you service the check valve.

Cut the waste pipe to the proper length and attach the silent check valve (Photo 2). Reassemble the pipes, open the shutoff valve and turn on the pump.

Silent check valves are available from most plumbing suppliers. If you have trouble locating one locally, search the internet for silent or soft close check valves.

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • 4-in-1 screwdriver
  • Bucket
  • Hacksaw

You'll also need rubber gloves

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

  • Silent check valve
  • Waste line pipe (to match existing)
  • Full port shutoff valve