How to Replace a Toilet Water Supply Valve

The water supply valve is on the left side behind the toilet tank.

The toilet water supply valve is used to turn off the water flow to your toilet whenever it needs servicing. It's on the wall or floor behind the toilet tank with a pipe running right up to the tank itself. Most people never even have to touch the toilet water supply valve and are unaware of it. But if the valve starts leaking, it's tough not to notice. If your toilet water supply valve is leaking, service it as soon as possible.

Things You'll Need

• Toilet tank hose
• 2 adjustable wrenches
• Rib-joint pliers
• Towel
• Plastic container

Instructions

1. Switch off your home's water supply valve. It's typically found near your home's water meter, which is either outside or in your basement.

2. Turn on the water flow in the sink closest to the toilet you're servicing. This clears up the water pressure so water doesn't burst out of the uncovered pipe when you remove the toilet water supply valve.

3. Remove the lid from your toilet tank and flush the toilet to empty the tank.

4. Slide your plastic container under the toilet water supply valve to catch water that drips from the pipe when you disconnect the valve. If you're still worried about water getting on the floor and causing damage, lay a small towel out under the plastic container.

5. Remove the lock nuts from the replacement valve so it's ready to go as soon as you remove the old one. Set the valve so it's "Off."

6. Remove the old toilet tank hose from the toilet tank, using an adjustable wrench or a pair of rib-joint pliers to unscrew it. Use your fingers to twist and pull it from the tank after you loosen it up.

7. Grip the toilet water supply valve, using one adjustable wrench to hold it steady as you loosen the nut holding the toilet water supply valve to the wall with another adjustable wrench.

8. Remove the old toilet water supply valve from the pipe. A small nut and metal ring should still be on the pipe after you remove the valve that can be reused to connect the new valve.

9. Place the new valve on the pipe quickly. Some water will flow from the pipe, even though the water supply is off, so try to get the replacement valve on the pipe right away.

10. Hold the new valve with one hand so the angled pipe on the valve is facing upward and turn the nut with your other hand to reattach it to the wall.

11. Hold the toilet water supply valve in place again, using one adjustable wrench, and tighten the nut holding the valve in place, using a second adjustable wrench. Make sure the valve stays vertical as you tighten the nut, with the pipe on the top of the valve always facing up.

12. Attach the new tank hose to the toilet water supply valve and screw it on tight. Connect the plastic end to the toilet tank, tightening it with your hand, and then tighten it one extra 1/4 turn.

13. Turn your home's water back on and carefully examine the toilet water supply valve for leaks. If it's leaking, tighten that area of the valve. Double-check for leaks after turning the valve on.

Tips & Warnings

• Try tightening the nuts on your toilet water supply valve with an adjustable wrench before replacing the valve. Don't turn the nut too tight, as you might damage the nut or the valve, causing even more damage.

• If you're unsure of what replacement valve to get, HomeOwner Series recommends a "1/4-turn angle ball stop with a 7/16 to 1/2-inch slip joint outlet" that comes in a "1/2-inch nominal compression inlet for copper pipe" or a "1/2-inch female iron pipe inlet for iron pipe." It's also recommended that you use a tank hose with a braided steel or nylon "1/2-inch female iron pipe inlet."

References

• HomeOwner Series: How to Fix a Toilet's Water Supply Valve (Part 1)
• HomeOwner Series: How to Fix a Toilet's Water Supply Valve (Part 2)
• Family Handyman: How to Fix a Leaking Shutoff Valve
• Family Handyman: How to Locate Your Gas Shutoff Valve and Water Shutoff Valve