What should you do if your toilet stops filling up? First, take the back off. Make sure the fill valve isn’t stuck closed (push down on the arm, water should flow). If not, you may need to replace the fill valve. Here’s a picture of a broken fill valve. The arm is stuck down, but no water is coming out:
Here’s how to replace it:
- Turn the tap on the supply clockwise to shut off.
- Drain the toilet tank by flushing it, then mop up what water is left with a towel.
- Disconnect the supply from the old fill valve.
- Remove the old fill value by undoing the nut on the bottom of the tank.
- Remove the supply line connector from the new fill valve. You shouldn’t need this, as there should already be one (the one you undid) on the supply tube. Then remove the grommet (black rubber ring) and the nut from the bottom of the new fill valve.
- Extend the height of the fill valve and move the float to the right position to match the old valve as closely as possible. In my case, that was making both as high as possible, and the new valve was still shorter than the old one.
- I actually put the big rubber washer on the inside of the tank (flat side down), then tightened the nut on the bottom of the tank (hand tight + one full turn with a wrench), push the grommet into the end of the fill valve, then reattached the supply (hand tight).
- Clip the fill tube to the inside of the overflow pipe, and slide the other end onto the fitting on the fill valve.
- Finally, turn on the supply, checking for leaks under the toilet as the tank fills up. The valve should shut off before the water level in the tank reaches the top of the overflow pipe. If not, you need to adjust the fill valve to make it shorter.
- Once the tank is full, test flush.
That’s all there is to it.