How to Flush Debris from a Toilet Fill Valve

A simple solution to try if your toilet won’t refill with water after flushing!

If you have a toilet that will not refill with water after flushing, then the fill valve is likely the source of the problem. Instead of immediately replacing the fill valve, you can try flushing out the fill valve with water to see if that fixes things. Often times, sediment and other debris in toilet tank water can prevent the fill valve from functioning properly. You might be able to get your toilet working again very easily with a quick flushing out of the fill valve!

Note: if you end up needing to replace the fill valve, then read my post on How to Replace the Toilet Fill Valve.

Step 1: Shut off water to the toilet

White toilet with water shutoff valve in silver, with blue annotated text
A toilet water shutoff valve. Turn clockwise to stop the flow of water to the toilet.

Locate the water shutoff valve – typically located behind and toward the bottom of the toilet. Turn the valve clockwise (until you can’t turn it anymore) to stop the flow of water to the toilet.

I would also recommend flushing the toilet now to remove some water from the tank.

Step 2: Remove the cap to the toilet fill valve

The fill valve I will be flushing out is a Fluidmaster 400AH:

This fill valve inside the toilet tank looks like this:

Looking inside a toilet tank at the fill valve, flush valve, and flapper
The toilet fill valve (white arrow) is often located off to one side of the toilet tank.

The gray cap on top of this fill valve can pop off. Simply grip and hold the shaft of the fill valve in one hand, then use your other hand to twist the cap (and lever arm) of the fill valve counter-clockwise. Depending on the exact fill valve, you might need to push the cap down as you twist it off (similar to opening a childproof medicine bottle where you need to squeeze and twist the cap simultaneously).

Once you remove the cap, the fill valve should look like this:

Gray toilet fill valve without cap
Toilet fill valve with the cap removed.

Step 3: Hold a small cup over the fill valve and turn the water back on

Take a small, empty cup and hold it upside down over the fill valve. This will prevent water from spraying and splashing all over the place.

Then turn water back on to the toilet by turning the water shutoff valve counter-clockwise. You should see water gush out of the fill valve, like this:

Water flowing from a fill valve without its cap on. Use an upside down cup to prevent water from spraying everywhere!

Let the water flush out the fill valve like this for 15-30 seconds.

Step 4: Shut off water to the toilet and replace the fill valve cap

This burst of water should flush out any sediment or debris that might have been preventing the fill valve from functioning properly. Now that it has been cleaned, you can replace the cap of the fill valve and twist it clockwise to secure it in place.

Step 5: Turn on water to the toilet

After turning on water to the toilet, flush the toilet to see if cleaning out the fill valve fixed the problem and if it can refill with water after flushing.

If your toilet still will not refill with water after flushing, then you need a new fill valve: check out my post on How to Replace the Toilet Fill Valve.

Did you find this guide useful? Let me know in the comments below!

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