How to Install a Sump Pump Check Valve

A sump pump.
  • 2-3 hours
  • Intermediate
  • 50-100
What You'll Need
Pipe cutter
Adapters or couplings
Sump pump check valve
Utility knife
PVC cement
PVC cement applicator
Pipe cleaner

If you have a sump pump installed in your basement, it is important to have a pump check valve. This is to ensure that the water being pumped out does not go back into the sump pit. The check valve is a type of fitting that can be attached to the ends of pipes. Inside this fitting, to put it quite simply, is a metal flap that remains closed until water (or oil) pressure forces it open. When the pressure ceases, it goes back to its closed position, preventing backflow.

Step 1 - Make Preparations

Check the diameter of your discharge pipe. Once you have determined this, go to your local hardware store and purchase the corresponding check valve with the correct diameter. Bring a sample of your pipe in order to test fit it to the pump check valve to be sure. There are a lot of check valves available. Choose whichever fits your needs. Also purchase the appropriate couplings that will fit the drainpipe.

Step 2 - Cut the Discharge Pipe

Now that you have your pump check valve, determine where you would like to place it on the discharge pipe. It is usually located near the sump pump, next to the sump pit in order to avoid too much water being trapped between the check valve and the pump. Use the pipe cutter to cut the discharge pipe in two places to make way for the new valve to be fitted. Make sure that you don’t cut too much. It’s better to cut little by little just to make sure. File the edges that have been cut to smooth them out.

Step 3 - Fit the Valve

Now that you have already created a gap in your discharge pipe, try to fit the check valve in the gap. It should fit perfectly since you carefully determined the appropriate size at the start. If the gap is too small to fit the pump check valve, cut some more of it away or just file it if the difference is small. Use some pipe cleaner on the cut ends of the discharge pipe and also on the pump check valve. Fit both ends of the cut discharge pipe into both ends of the valve and secure it. Use the couplings to join all the ends together.

Step 4 - Add Finishing Touches and Test

Now that the pump check valve is in place, use some PVC cement to seal the points of contact. Put some cement in the applicator and carefully apply it across the gaps between the connections. Let the cement dry and clean the area thoroughly, making sure that no gaps were missed. Test the check valve by opening the pump and pumping out some water from the sump pit. Listen carefully to the valve as water pressure runs through initially. You should hear the flap inside the valve swinging open. When the water pressure ceases when you kill the pump, you should hear the flap inside the pump check valve closing.