How To Install A Toilet Fill Valve

Learning how to install a toilet fill valve is relatively simple. The first step is knowing what you’re working with.

A fill valve is sometimes referred to as a ball cock. They come in all shapes and sizes.

The type I’ll be discussing will work for most standard toilets and can be found at your local home store. I like them because they’re simple and they work.

I don’t recommend getting variations of the model I mention. Plumbing parts should be simple, like plumbers.

Fluidmaster 400A Universal Fill Valve

The Fluidmaster 400A universal fill valve is simple and inexpensive. You can find it anywhere.

Fluidmaster sells variations of this model but I don’t recommend them. How to install a toilet fill valve, toilet ball cock, Lee's Summit plumberIf you have an older style fill valve with a ball float this model usually replaces it.

Once this is installed you should never need a tool again to replace it. Don’t worry if the packaging is a little different as long as you see all the parts in this illiustration.

Before We Begin

Before we begin learning how to install a toilet fill valve you’re going to need a few things. A few tools are always necessary before beginning a plumbing repair.

And I always recommend the best you can afford. It’ll make the job go smoother. What you’ll need for this repair are:

  • Pliers
  • Knife
  • Towel or rag

How To Install A Fill Valve

The following is a step by step explanation of how to install a fill valve. There are different ways to do this. But this is the way I prefer and it’s worked well for me.

  1. Turn off the water at the water shut offs. If you have an older model shut off I’d recommend either replacing your water shut off or shutting the water off to your home.
  2. Flush the toilet. Hold the handle down to get as much water out as possible.
  3. Using either your towel or a wet vac, remove the remaining water from inside the tank.
  4. Remove the water supply pipe from the bottom of the fill valve.
  5. Remove the fill valve lock nut holding it to the tank.
  6. Remove the refill tube from the flush valve overflow tube and pull out the old fill valve.
  7. Pull apart the shank washer and cone washer that comes with the fill valve.
  8. Put the shank washer on the shank of the fill valve with the smooth side facing the flange on the fill valve shank.
  9. Place the fill valve through the opening at the bottom of the tank.
  10. Thread the lock nut on the bottom of the fill valve. Tighten it a little beyond hand tight. Don’t over tighten it. It could cause a crack in the fill valve.
  11. Place the angle adapter onto the flush valve overflow tube. Be careful not to crack the plastic overflow tube.
  12. Place the refill tube on the fill valve refill tube barb and attach the other end of the refill tube to the angle adapter. If the refill tube is too long, cut the excess off and reinstall it.
  13. Reattach the water supply tube to the bottom of the fill valve. I don’t recommend keeping the ridgid chrome style water supply tubes. I prefer replacing them with stainless steel flexible supply tubes.
  14. Confirm that the adjustment nut on the shaft of the fill valve is locked in position and turn the water on slowly.
  15. After the fill valve has filled the tank, adjust the water level by turning the plastic rod on the float. It will raise or lower the float to adjust the water level. If you need at least 3 or 4 inches of water level adjustment you will need to shut the water off again and pull up on the adjustment nut on the shaft of the fill valve. This will allow for larger water level adjustments. Just be sure that it’s pulled all the way back down into the locked position before turning the water back on.
  16. Check for leaks.
  17. Put about ten feet of toilet paper in the bowl and flush it. This is a good test for a proper water level adjustment.

Clear As Mud?

I know that’s a lot of instruction and not very many pictures. But it’s not nearly as complicated as I’ve made it sound.

Understand, I’m just trying to be thorough. This is plumbing 101. You’ve got this.

And if you don’t or you just don’t wanna do it, call Advocate Master Plumbing. I’ll let you watch while I install it so you can know how to do it the next time.

And remember, you’ll always get a master plumber in your home when you call the locally owned and family operated plumbing service company at Advocate Master Plumbing.

We also install and repair hot water heaters, sump pumps, garbage disposals, water pressure regulating valves, toilets, faucets, gas pipes, water pipes and drain pipes.

And don’t forget to check out our 5 STAR reviews on Google, YELP & Facebook.


Here’s a video that may help those visual learners.


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