How to Install a Laundry Shut-Off Valve

In one project, homeowner Joyce explained why she was so diligent about shutting off her washing machine valves manually: “I turn them off every time I finish a wash. And it’s difficult, it’s inconvenient, and I have a little bit of touch of arthritis, and it’s hard for me to do.” When Richard asked about a previous water leak, Joyce recalled, “Oh my, it was a foot deep in the basement.” That kind of experience is exactly why an automatic shut-off valve is such a worthwhile upgrade—it eliminates the need to wrestle with manual valves after every load.

In this video, This Old House plumbing and heating contractor Richard Trethewey installs a laundry shut-off valve.

Steps:

1. Close the existing shut-off valves that provide hot and cold water to the washing machine.

2. Use a wrench to disconnect both washing machine hoses from the valves; use a rag to catch any drips.

3. Tighten an adapter onto each of the hot- and cold-water shut-off valves.

4. Measure and cut plastic pipe to span from the adapters to the elbows on the automatic shut-off valve.

5. Assemble the plastic pipe and fittings using PVC primer and cement.

6. Thread an adapter onto the hot- and cold-water side of the automatic shut-off valve.

7. Hold the automatic shut-off valve in position against the wall, and mark the two mounting holes.

8. Drill holes on the marks and install hollow-wall anchors.

9. Screw the shut-off valve to the wall.

10. Reconnect the hot- and cold-water washing machine hoses. Then open the water shut-off valves.

11. Place leak sensor on floor and, then connect it to the automatic shut-off valve.

12. Plug washing machines power cord into the automatic shut-off valve, then plug the valve into the wall outlet.

How the Leak Sensor Works: The automatic shut-off valve protects against hose failures, but the included leak sensor adds another line of defense. It has two contacts at the bottom and sits on the floor right behind the washer. If the washing machine overflows or there’s a stoppage in the drain, the sensor detects water and signals the valve to close—covering scenarios that go beyond just a burst hose.

Pro Tip: Richard Trethewey, This Old House plumbing and heating expert, explains that when the automatic shut-off valve first came onto the market, it could only be installed inside of a recessed box, meaning you had to modify the plumbing inside the walls and could only do it in new installations. But the manufacturer came out with an adapter kit that is designed to go right onto existing hose connections, making retrofit installation possible without opening up walls.