Replace Your Main Water Shut-Off Valve

Time: 10 mins

No one wants to think about plumbing gone wrong, but toilets clog and so do sinks. Some clogs are worse than others and sometimes you’ll even need to turn off the water completely. That’s a no-go if the shut-off valve is broken. Learn how to test and replace your main water shut-off valve before you need to use it.

What's in it for you?

  • Prevent flooding
  • Prevent expensive water damage
  • Peace of mind

(Show me how)

Test Your Main Water Shut-Off Valve

  1. Find your main water shut-off valve. Follow your water line until you see a knob or lever. It’ll either be in the basement or on an outside wall (often in the front corner of the house). If you have an older house, you’re more likely to see a knob (gate valve); newer houses are more likely to have a lever (ball valve).

  2. Check for signs of corrosion. See any white, turquoise, or brown residue on the outside of the valve? That means your valve is probably corroded, especially if the residue doesn’t brush off. (Older valves are especially prone to mineral build-up.)

  3. Turn the knob or lever to test the shut-off mechanism. If it’s stuck or there are visible signs of corrosion, you’ll need to either clean the valve or replace it. We suggest replacing it — it's easier than cleaning.

(Show me how)

Replace Your Main Water Shut-Off Valve

  1. Get a replacement valve. Head over to your local hardware store and grab a replacement valve. Try to get a ball valve even if you currently have a gate valve. Ball valves are less prone to leaks and they last longer.

  2. Detach the water supply lines. There are a lot of pipes attached to your valve that bring water to it or to other areas of the house. Use a wrench to unscrew the nuts holding these pipes in place. It’s ok to let the lines dangle for now — just be sure to have a bowl nearby to catch any drips.

  3. Remove the old water shut-off valve. Find the compression nut and use your wrench to unscrew it. (It’s the one closest to the knob or lever.) Psst...you’ll need to hold the valve in place with a pipe wrench while you’re doing this to keep the knob from turning. Ta-da! The valve should now slide right off the pipe. Is your valve soldered in place? Don’t fret. You can cut the pipe with a tubing cutter or hacksaw — just cut as close to the compression nut as possible.

  4. Prepare the pipe for the new water shut-off valve. You’ll see threads on the pipe where the valve used to be. Grab a cloth and clean them thoroughly to remove any residue. Keep the seal between the valve and the pipe airtight by wrapping thread seal tape around the threads. No leaks here, people.

  5. Install the new water shut-off valve. Slide it onto the pipe and attach with a compression nut. Reattach the water supply lines. Grab your wrench and tighten everything so it fits snugly.

Pro Tip: Check your pipe twice a year. That’s the perfect amount to keep corrosion at bay.

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