How to Replace a Toilet Fill Valve

How to Replace a Toilet Fill Valve – disconnect the PVC water supply hose and remove the old ballcock float ball valve. This project is continued from How to Replace a Toilet Fill Valve – Part 1.

Disconnect the Toilet Water Supply Hose

Unscrew the coupling nut that attaches the water supply hose to the toilet fill valve. This is located under the tank on the left side of the toilet. The nut usually has large “wings” to unscrew by hand. Use a large adjustable wrench if the plastic nut is stuck.

Take care to shut off the water supply valve (valve at the bottom of the photo) before unscrewing the nut or you’ll have water gushing out and flood the bathroom!

Replace a Toilet Fill Valve: Remove the Water Supply Hose Coupling Nut

The water supply hose nut is unscrewed from the fill valve threads. The supply hose is now loose – several ounces of water will run out of the fill valve. Use a towel to catch the water.

Toilet Repair: Disconnect the Water Supply Hose

The toilet fill valve lock nut holds the valve body against the toilet tank. Use a 10-inch adjustable wrench (or channel locks will do in a pinch) to unscrew the nut:

Replace a Toilet Fill Valve: Unscrew the Lock Nut

The fill valve is loose inside the tank when the lock nut is removed:

Replace a Toilet Fill Valve: Lock Nut and Toilet Tank

If you are not replacing the water supply hose, skip the next two steps.

Because I’m replacing the toilet connector PVC plastic hose with a reinforced Brasscraft hose, the old plastic supply hose is removed and discarded. Unscrew the compression nut with the adjustable wrench. If the nut is unusually tight, place a second wrench on the valve body to avoid torquing the copper water pipe:

Toilet Shutoff Valve: Unscrew the Water Supply Host Compression Nut

Here’s the old PVC supply hose (a.k.a. toilet connector). While I’ve not had a PVC supply hose fail on me and cause flooding, this $2 plastic hose is simple to replace with a $6 reinforced Brasscraft toilet connector hose.

Toilet Repair: Old PVC Connector Hose

Remove the Toilet Ballcock Fill Valve

After unscrewing the lock nut, the old ballcock fill valve simply lifts out of the tank:

Replace a Toilet Fill Valve: Lift the old Ballcock Valve out of Tank

The toilet tank is ready for the new fill valve and flapper. Now’s a good time to wipe down the inside of tank to remove any remaining sediment and iron stains that couldn’t be reached previously:

Replace a Toilet Fill Valve: Toilet Tank Ready for New Valve

View of the water supply shutoff valve and bottom of toilet tank. The reinforced Brasscraft toilet connector hose will be installed here:

Toilet Repair: Water Supply Valve and Tank Ready new Connector Hose

This project is continued in How to Replace a Toilet Fill Valve – Part 3.

Thanks for reading,

Bob Jackson

6 Comments

Elizabeth June 27, 2015 at 8:26 pm - Reply
The coupling nut that attaches the water supply hose to the toilet fill valve will not come off. It just keeps turning and turning, even if we try to hold the part that is in the toliet still.
- Bob Jackson June 28, 2015 at 10:39 am - Reply
  You can’t remove water supply hose nut because it’s spinning in place, correct? I’m guessing the plastic threads are stripped.
  Wedge the tip of a flat blade screw driver in the seam between the hose nut and fill valve lock nut – it’s the gap between my index finger and thumb. Twist the screw driver (not too hard!) to force the hose nut downward while unscrewing it. That should engage enough of the stripped threads to get it off the fill valve stem.
  - Jem November 25, 2017 at 7:04 am - Reply
    I have the same issue
    I installed the full valve. Then secured the lock nut under the tank. The instructions said not too tight so I stopped turning when I heard a creak/ cinch sound. Then I proceeded to attach the water supply line to the fill valve threads. I thought I had decided the coupling nut well but when I turned on the water, there was leaking. The leak was from the coupling nut connection point. I tried to unscrew the coupling nut, and the fill valve in the tank rotates. I tried to hold it still so it doesn’t rotate then I noticed the height begins to adjust. How do I undo the whole set up so I can start over?
    - Bob Jackson November 25, 2017 at 3:39 pm - Reply
      The new fill valve is installed in this project. Hold the fill valve by the black plastic shank near the base when tightening the lock nut against the bottom of the tank.
      If you grasp the gray outer shank or lock ring the valve will spin changing the float height and fill level.
Amanda August 4, 2015 at 5:11 pm - Reply
I cannot get the water supply hose nut loose at all, and it’s not spinning in place. Someone got it on there tight.
Any suggestions?
Thanks!
- Bob Jackson August 4, 2015 at 6:38 pm - Reply
  Loosen the nut with a pair of channel locks.