How to Replace Toilet Fill Valve

Start by turning off the water supply to the toilet. Flush the toilet and hold the handle down to drain most of the water from the tank. Next, use a sponge to remove any remaining water.

Disconnect the water supply line (some water may drain out), remove the mounting nut, and lift the old fill valve out of the tank.

Setting the correct height of your fill valve controls how much water enters the tank and is a critical step.

• Too high: The valve won't shut off, and you run the risk of the valve constantly running or overflowing.
• Too Low: There won't be enough water in the tank, leading to weak or incomplete flushes.

To adjust the height of a Korky valve, hold the bottom and twist the top of the valve counterclockwise to the unlocked position. Then slide the fill valve up to full extension, then place the valve into the tank hole.

Next, push down on the top until the water level mark sits about 1/2" below the top of the flush valve overflow tube. This mark is stamped on all Korky fill valves.

Once the correct height is set, remove the valve and twist the top clockwise to lock it in place. The ribs will align with the pegs when properly locked. Then attach the refill tube to the fill valve.

Place the fill valve into the tank hole at a 45-degree angle from the back of the tank. This ensures the refill tube will have a straight path to the overflow tube.

Next, install the mounting nut with the beveled side up and hand-tighten only.

Attach the refill tube to the overflow tube using the included metal clip.

Some Kohler® flush valves may use the metal clip or require the refill tube to be pressed into the top.

For Mansfield® tower-style flush valves, insert the refill tube without the clip and leavce 1/2" of clearance above the black flush valve opening.

Connect the water supply to the bottom of the fill valve under the tank. Hand-tighten this part only and avoid using sealants or tape.

Then slowly turn the water supply on and observe the tank filling. It's normal for water to flow from 3 areas:

1. The refill tube
2. The top of the valve
3. The base of the valve

Model-Specific Next Steps

• 528 (white cap) or 528T (blue cap): Installation is complete.
• 528MP (silver cap) or 528X (black cap): Turn the refill adjuster dial clockwise to open, then proceed to the final adjustment step.

Adjusting the refill setting ensures the bowl receives the right amount of water and helps reduce water waste.

To adjust:

1. Flush the toilet and wait 2 minutes for the bowl water level to settle.
2. Mark the bowl's water line with a pencil or dry-erase marker.

3. Flush again and observe when the water reaches the mark in the bowl and when the fill valve shuts off.

Make adjustments as needed:

• Within 1/2 inch of the mark: No adjustment is needed
• Below the mark: Turn the dial clockwise to increase flow
• Above the mark: Turn the dial counterclockwise to reduce flow.

Fine-tuning may take a few attempts. Once set, your fill valve will match your toilet's original performance.

How to Fix a Fill Valve that Won't Shut Off

If your fill valve continues to run or won't shut off:

• Confirm the fill valve height is set below the top of the flush valve overflow tube
• Re-adjust the height if needed and ensure it locks into place
• Make sure the refill tube is not pushed into the overflow tube; this can create a siphon.

Valve is Filling Slowly/Not Filling

First check the basics:

• Make sure the water supply valve is fully open
• Confirm the supply line is not kinked or restricted

If there is little to no water flow:

1. Turn off the water supply
2. Disconnect the supply line from the fill valve
3. Place the end of the supply line into a bucket
4. Turn the water supply on
   1. No water flow: The issue is with the home's water supply (contact a plumber)
   2. Water flows normally: Check the fill valve inlet for obstructions. If there are no obstructions, watch our fill valve servicing video.

Water Periodically Turning On and Off

This usually indicates a slow leak from the tank.

1. Turn off the water supply
2. Mark the current water level in the tank with a pencil
3. Leave the water off for about 30 minutes

If the water level drops during this time:

• The flapper or flush valve seal is leaking, causing the fill valve to cycle on
• Check that the flapper chain has proper slack (not too tight)
• Make sure the flapper or seal is clean and free of debris
• Inspect the flush valve sealing surface for residue or buildup
• If the flapper or seal is worn or old, replacing it is recommended.

Customer Service

Was your issue not listed? Give our customer service team a call at 1(800)528-3553 or send us an email at customer@lavelle.com.