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How to Replace a Fill Valve

A toilet fill valve controls the amount of water in the toilet tank. Once you flush the toilet, the fill valve lets in only the required amount of water into the tank. However, the valve may become faulty with time and stop functioning properly. A faulty fill valve allows excess water into the tank. Therefore, fill valves should be replaced after a certain period to ensure proper performance.


1.  Turn off the water supply to the tank. This prevents water from spilling onto the floor once the supply pipe is disconnected.

2.  Take off the lid to open the tank.

3.  Flush the toilet to get rid of the water inside the tank.

4.  Disconnect the supply pipe from the toilet tank.

5.  Open the nut that holds the fill valve in position under the tank.

6.  Let the water remaining in the tank drain into a bucket placed under the tank. The water can also be removed by soaking it up with a piece of cloth or a sponge.

7.  Reach out to the bottom of the tank and loosen the nut holding the fill valve onto the tank.

8.  Remove the old fill valve from the tank and replace it with a new one.

9.  Adjust the new fill valve to fit the size of the water tank. It should be about an inch above the overflow tube.

10. Once the new fill valve is in position, replace the nut that holds it onto the bottom of the tank.

11. Connect the overflow pipe to the fill valve and adjust its position.

12. Reconnect the supply pipe to the bottom of the fill valve from the bottom of the tank.

13. Make sure that all nuts are well tightened.

14. Open the water supply to allow water to flow into the tank.

15. Check the bottom of the tank for leaks and ensure that the fill valve and overflow pipe are in the proper positions.

16. Flush the toilet and watch the refill to ensure everything is working perfectly before replacing the lid.

Kevin L. Sharp