Is your toilet refusing to refill after you flush? The most common cause is a faulty toilet fill valve (also called a flush valve). Sometimes the flapper valve may also need replacing if both parts are failing. Below are detailed instructions to help you diagnose the issue, replace faulty parts, and get your toilet working again
What Does the Toilet Fill Valve Do?
The fill valve regulates the amount of water flowing into the toilet tank. There are two main types:
- Older Ball Valve
A plastic ball is attached to a metal rod. As the ball moves with the water level, it opens or closes the water supply. - Fluidmaster-Style Valve (Universal)
A round plastic float moves up and down on a cylinder. This float opens or closes the water flow to refill the tank.
A fill valve should be replaced if it doesn’t shut off correctly, fails to refill the toilet, appears damaged, or is heavily corroded.
Cost and Parts
- Toilet Fill Valve: A new one typically costs under $20, with many universal options around $15.
- Replacement Flapper (If Needed): Flappers are usually under $10.
- Brands: Kohler, Toto, and American Standard often accept universal replacement parts.
- Where to Buy: Hardware stores like The Home Depot carry universal valves and other supplies.
Universal fill valves fit about 98% of all toilets, making them a great budget-friendly fix.
Troubleshooting Before Replacing Parts
Try these steps first to confirm you need a new fill valve:
- Check the Water Supply
- Look behind or beneath the toilet for a small silver or chrome valve.
- Make sure it is fully turned on (counterclockwise). If it’s off or partially closed, the tank won’t refill properly.
- Check if the Fill Valve Float Is Stuck
- Remove the tank lid.
- Make sure no debris or mineral buildup is preventing the float from moving up and down.
- Gently lift and lower the float to see if it moves smoothly.
- Check the Fill Valve Adjustment
- Some fill valves have an adjustable height that sets how high the tank fills.
- If it’s set too low, water might not flow in. If it’s too high, water may run continuously.
- Look for a screw or clip on the valve to raise or lower the float.
- Check the Ball Float (Older Style Valves)
- On older toilets, the ball float is attached to a metal rod.
- Over time, the rod can bend, or the ball can detach.
- Gently bend the rod upward or downward to adjust the water level in the tank.
Replacing the Toilet Fill Valve
If the steps above don’t resolve the issue, follow these detailed instructions:
1. Gather Your Tools and Supplies
Adjustable wrench or pliers
A new universal fill valve
Towel or small container to catch drips
Optional: Teflon tape to create a tighter seal (useful on the threads)
2. Turn Off the Water and Flush
Turn the silver or chrome shut-off valve on the wall fully clockwise to stop the flow of water.
Flush the toilet to drain as much water as possible from the tank.
Use a towel or container to soak up any remaining water in the tank.
3. Disconnect and Remove the Old Fill Valve
Locate the fill valve’s plastic nut underneath the toilet tank.
Use pliers or an adjustable wrench to loosen and remove this nut. Water will likely drip out, so keep towels or a container ready.
Inside the tank, twist the base of the fill valve counterclockwise to free it.
Remove any rubber washer or gasket that seals the valve to the tank. Keep it in case the new valve’s washer doesn’t fit perfectly.
4. Prepare and Install the New Fill Valve
Adjust the height of the new valve so it will sit properly in your tank. Most universal valves have a locking ring or a twist mechanism that lets you slide the top portion up or down.
Insert the new valve into the opening in the toilet tank.
Position the rubber washer or gasket on the valve’s base according to the instructions provided.\
From under the tank, tighten the plastic nut by hand first, then use pliers to give it a final snug turn. Avoid overtightening to prevent damage.
If needed, wrap a bit of Teflon tape around the valve threads before attaching the water supply line.
5. Reconnect the Water Supply
Attach the water supply line to the bottom of the new fill valve.
Turn the shut-off valve on the wall counterclockwise to restore water flow.
6. Adjust and Test
Observe the tank as it refills. Listen for any strange noises or signs of leaks around the new valve.
If the water level is too high or too low, use the adjustment screw or clip on the fill valve to change the float level.
Once you have the desired water level (usually about one inch below the overflow tube), flush the toilet to confirm everything works properly.
Here is a .PDF that you can view that has a highly detailed step-by-step procedure for removing and replacing your toilet fill valve. These are the instructions for the most common universal water fill valve replacement and will help you every step of the way.
Replacing the Flapper (If Needed)
If the flapper is worn or not sealing:
- Turn off the Water
Shut off the wall valve again and flush the toilet. - Remove Old Flapper
Detach it from the flush valve’s pegs or clips. - Install New Flapper
Attach the new flapper using the same clips or pins. - Test for Leaks
Turn the water back on and allow the tank to fill. Put a few drops of food coloring in the tank. Wait 30 minutes. If you see color in the toilet bowl, the flapper may not be sealing well.
Extra Tips and Maintenance
- Clean the Tank: While the tank is empty, consider wiping away rust or mineral deposits.
- Inspect Other Parts: Check the flush handle, tank bolts, and the overflow tube for any visible damage.
- Flush the Line: Before installing a new valve, you can briefly turn on the water supply with the valve out of the tank to rinse out debris.
- Check for Slow Leaks: After installation, watch the tank level over time. If it slowly drops, there may be a seal issue with the flapper or the fill valve.
- Use Quality Parts: Spending a few extra dollars on a well-reviewed universal valve can extend the life of your repair.
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