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If you have an older toilet, a faulty fill valve can cause it to leak, wasting water and money. Generally, your best bet is to replace it. It won’t take much time, and in this video, we’ll show you how to do it yourself. You may be interested in our How to Replace a Toilet video.

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If you have an older toilet, a faulty fill valve can cause it to leak, wasting water and money. Generally, your best bet is to replace it. It won’t take you much time, and the replacement part isn’t expensive.

In the next few minutes, I’ll show you how to put a new fill valve on your toilet. If your toilet is having other problems, watch our video “Diagnosing a Leaky Toilet” to figure out which component inside the tank might be leaking.

The fill valve lets water into the tank and a float keeps the water in the tank from getting too high. The valve assembly includes the float and a shut-off mechanism to stop the flow of water.

Before you visit your local independent home improvement retailer to pick up your new fill valve, here’s something you should know. The best fill valves offer anti-siphon protection. In fact, your local building codes may require this type of valve. Anti-siphon protection prevents toilet tank water from getting siphoned back into your home’s water supply. Regardless of your building codes, installing an anti-siphon valve is a good idea.

Start by turning off the water supply to the toilet.

Remove the lid to the tank. Inside the toilet, you’ll want to remove the refill tube attached to the overflow pipe on the flush valve.

Flush the toilet by holding down the tank lever to get as much water as possible out of the tank. You can use a sponge or a towel to get the rest of the water out.

Next, disconnect the water supply line from the tank. You may need to use an adjustable wrench or a pair of channel locking pliers to loosen the connection.

Then remove the old fill valve by removing the lock nut beneath the tank.

The new fill valve goes on the way the old one came off. Place the shank washer over the threads of the shank on the new valve, flat side up. Then insert the fill valve into the hole in the bottom of the tank.

While holding it in place, use a tape measure to see if the valve is set at the proper height in relation to the overflow pipe. If you need to adjust the height of the valve, press up on the lock ring to disengage it and turn the shank to adjust the fill valve to the proper height. Once it’s set to the correct height, pull the lock ring back down to lock the shank in place.

Don’t forget to attach the refill tube to the top of the overflow pipe.

Finally, reattach the water supply connection beneath the tank and turn on the water. Finally flush the toilet to make sure that if it fills back up properly, and check for any leaks beneath the toilet. If the valve is leaking under the tank, tighten the connections.

If you have questions about this or any other home improvement project, be sure to read our list of Frequently Asked Questions for this video. And be sure to print out our Project Instructions, which includes a Tools and Materials checklist, before visiting your local independent home improvement retailer. That’s where you’ll find all the products and helpful advice to complete your project. If you’re not sure where to find your local store, check out our Store Locator.

Good luck with your project and thanks for watching.

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  1. 1.remove lid

    Remove lid from tank.

  2. 2.Turn off water

    Shut off water by turning the shut-off valve clockwise.

  3. 3.drain water from tank

    Drain as much water out of tank as possible by holding flush lever down until toilet is completely flushed.

  4. 4.towel out water

    Sponge or towel out any remaining water in the tank. A shop vac also works well.

  5. 5.disconnect water

    Disconnect the water supply tube or hose that connects the water supply valve to the fill valve.

  6. 6.loosen locknut

    Beneath the tank, loosen the lock nut that holds the fill valve to the tank.

  7. 7.remove old fill valve

    Remove the old fill valve.

  8. 8.insert new fill valve

    The new fill valve will go on similar to how the old one came off.

  9. 9.reattach fill valve

    Reattach new fill valve and adjust float to correct height according to manufacturer’s instructions.

  10. 10.attach new refill tube

    Attach new refill tube to overflow pipe.

  11. 11.reattach water supply tube

    Reattach water supply tube or hose to tank.

  12. 12.Install new valve

    Turn on water, test new fill valve and check for leaks.


Project Faqs « back to project


What is an anti-siphon toilet fill valve?

The anti-siphon protection prevents the toilet tank water from getting into your home water supply... More »

My toilet is constantly running causing ripples in the bowl. What’s wrong?

Either the float on the fill valve is stuck or it is set too high, causing water to overflow from the tank into the bowl through the overflow tube.... More »


How do I test my toilet flapper for leaks?

Test your toilet flapper by pouring a bit of food coloring into the tank, then check back in 15 minutes to see if the water in the bowl has changed... More »

How do I adjust toilet water level?

To adjust the water level on a toilet with modern tank components, there is a lock ring or pinch clamp that allows you to raise or lower the float... More »

How do I replace a damaged refill valve?

Turn off the toilet’s water supply valve, flush the toilet and sponge out any remaining water in the tank. The refill valve is usually removed by... More »

Can I test to see if the leak is coming from the refill or the flush valve?

Yes. Shut off the water supply to the toilet. Mark the water level on the inside of the tank with a pencil. Check the water level in 10 or 20... More »

Why is water constantly running into my toilet?

If the refill valve is leaking, the tank overfills and the excess water runs into the overflow pipe and into the... More »

How high should the water level in the toilet tank be?

It needs to be high enough for complete flushes, but it should be below the top of the overflow pipe. The tank should have a colored or molded water... More »

Why isn't my toilet bowl filling up?

See if you toilet has an overflow pipe. If so, a rubber tube should go into it. It has a metal clip on it and sometimes it can come... More »

I’ve heard I need to open a shut-off valve (either a ball or a gate valve) before soldering it to a copper pipe. Why?

By opening the valve it prevents the washer inside the valve from getting damaged by excessive heat when... More »

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Comments (2)

  1. In photo #11, hand tighten, never use a wrench or a channel lock. Too often, the tool over tightens and causes damage.

    August 8, 2011 at 4:03 pm
  2. Had to replace the fill valve and the flush valve this morning on my toilet. Glad I had those two videos available to let me know what I was getting myself into tackling the job myself. Wasn’t hard at all and only took about 30 minutes total for both.

    July 2, 2012 at 1:17 pm