How to Replace a Leaky Water Supply Line in a Toilet

If you have noticed water stains around the base of your toilet, a leaky water supply line is a possible cause. This line connects the faucet extending from the main water line to the tank on the toilet. Over time, the line can corrode and split. This inexpensive repair takes less than 10 minutes to complete, but it can save you thousands of dollars in floor repairs if you spot the leak early.

Things You'll Need

• Adjustable wrench
• Towel
• Tape measure

Instructions

1. Turn off the water supply faucet. Place a towel under the water supply line to catch any water that leaks out of the line when you remove it.

2. Turn the coupling connecting the water supply line to the faucet clockwise to remove it. You may be able to remove the coupling with your fingers. If not, use an adjustable wrench.

3. Remove the plastic coupling from the underside of the toilet tank, turning it counterclockwise. On most models, the water supply line connects to the left side of the tank.

4. Measure the diameter of the coupling on each end, using a tape measure. Supply lines come in different coupling sizes, such as 3/8 inch, 1/2 inch and 7/8 inch. Also, the couplings are not always the same size on each end.

5. Connect the new supply line to the toilet tank, tightening it with your fingers. Give the coupling an extra 1/4 turn with an adjustable wrench to make sure it is tight. Repeat this step with the other end of the supply line, connecting it to the water faucet.

6. Turn on the faucet and let the toilet tank fill. Inspect the new water supply line for leaks.

Tips & Warnings

• Choose a water supply line reinforced with braided steel. It may cost $2 or $3 more, but it will outlive cheaper types of water supply lines.

References

• This Old House: Fixing a Leaky Toilet