Step 4 · Install the Backwater Valve

This is the step most people slow down on. Take it one move at a time — there’s no rush, and you can rewind the clip as many times as you need.

First, perform a 'dry fit'. Assemble the backwater valve and two slip couplings onto the cut pipe ends without any primer or cement to ensure all parts align correctly and the valve sits level. Crucially, check the flow-direction arrow molded into the valve body; it MUST point away from the house and toward the street sewer. Once the fit is confirmed, disassemble the parts. Working one joint at a time, apply the purple PVC primer to the outside of the pipe end and the inside of the coupling. Immediately follow with a liberal application of PVC cement to both primed surfaces. Push the coupling onto the pipe with a quarter-turn twisting motion to spread the cement evenly. Hold firmly for 30 seconds. Repeat this process for the other pipe end and coupling. Finally, prime and cement the valve spigots and the open ends of the couplings, and push the valve firmly into place, again using a slight twist. Use a level to confirm the valve is not tilted.