Toilet Leaking From the Fill Valve — Repair It in 8 Steps

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A leaky toilet fill valve can cause a lot of problems — from disabling your toilet to flooding the bathroom floor. When you notice the toilet leaking from the fill valve, the only solution is to replace it.

It’s not a complicated project as you can do it in eight simple steps. Let us show you how!

Where Is the Fill Valve?

The toilet fill valve is a tall plastic element residing in the toilet tank. The fill valve is the tallest part of the tank, so you can see it standing proudly next to the overflow pipe.

If you are directly facing the tank, you will see that the entrance of the fill valve is on the left side of the tank’s bottom. This is where the plastic tube connects to the external water supply line, AKA the pipe leading the water into the tank.

The outlet pipe leads the water from the tank through the flush valve and into the toilet bowl when you flush the toilet. But if the fill valve is malfunctioning, your toilet is losing water

How to Fix a Toilet Leaking From the Fill Valve?

A leaky fill valve is damaged, so the only way to fix the toilet is to replace this part. The good thing is that the toilet fill valve is easy to access and fairly affordable. Here are eight steps you should take to replace the fill valve.

Step 1: Close the Water Supply Valve

The first task is to close the water supply valve. The shutoff valve is on the wall behind your toilet, so you can approach it and turn the knob clockwise. That way, you will stop the water from flowing into the toilet tank.

If the shutoff valve won’t shut off, spray it with WD-40 penetrating oil. It’s a substance that loosens hard and rusty metal elements, so you can get the knob going even if it’s old and out of use for years.

Step 2: Empty the Tank

Now that the water can’t run through the supply hose, you can press the flush lever and empty the tank. Press the flush lever a little longer than usual to remove almost all water from the tank.

When you do it, you can uncover the tank by removing the lid — pull the top with your hands, and it should come off. If it’s too stiff, use a flathead screwdriver to detach the lid from the tank.

Without the top, you can see the inside of the tank — clean the remaining water droplets using a sponge or dry towels.

Step 3: Remove the Supply Hose

There’s no water in the tank anymore, which allows you to detach the water supply line, too. It’s a metal coupling that pairs the shutoff valve with the fill valve. Only a small nut connects it to the fill valve, so you can remove the hose quickly.

Unscrew the threaded nut with your fingers — move it counterclockwise, and you’ll see the nut falling off. If you can’t do it with your hands, use a pair of pliers. Unscrew the nut slowly so it doesn’t crack or damage the pipe.

Step 4: Loosen the Fill Valve

Now you need to loosen the valve by removing the nut holding it against the tank bottom. The process is the same — unscrew the plastic or metal nut by turning it counterclockwise. 

Without the nut, only gravity will keep the old fill valve standing in the toilet tank.

Step 5: Remove the Valve

Removing the old fill valve is as easy as picking it up with your fingers. Remember that it’s a lightweight plastic tube, so it doesn’t require strength to lift it from its seat.

But before doing that, don’t forget to disconnect the fill tube. It’s a thin rubber tube connecting the valve with the overflow pipe — you just need to pinch the fill tube with your fingers and remove one of its ends from the valve.

Throw the old valve into the trash can.

Step 6: Install the New Valve

You can now install the new fill valve in the tank. It’s the easiest phase of the project because you only need to put the valve back in its original position. However, make sure that it stands high above everything else in the tank.

The fill valve should be an inch below the tank top and certainly a couple of inches higher than the overflow tube. After installing the valve, put back the fill tube to connect the overflow pipe with the fill valve.

Remember to screw the nut that keeps the valve in its position — use pliers or an adjustable wrench to screw the nut clockwise. It will seal the valve and prevent future leakages.

Step 7: Reconnect the Supply Hose

Now it’s time to reconnect the supply line. You must attach the metal pipe to the fill valve and then secure it with the nut. Once again, turn the nut clockwise to tighten the hosepipe — it will help you establish water flow without leaks. 

Step 8: Open the Shutoff Valve

You’re almost done! The only thing left is to open the shutoff valve. Use pliers to turn the knob counterclockwise until the valve is fully open. As soon as you do it, you’ll hear water flowing into the tank again.

We recommend flushing the toilet a few times to make sure there are no leakages anymore. You can check if the valve is still leaking by placing paper towels underneath — if they don’t get wet, the fill valve is working adequately.

The Bottom Line

Whenever you notice a leaking toilet tank, you should check the fill valve first. This little part controls the water flow in your toilet, but it breaks down over time and causes leakages.

The good thing is that replacing the fill valve is very simple — you only need to follow our instructions step by step. The whole process will take you no more than 15 minutes, so what the heck are you waiting for?


Can a fill valve cause the toilet to leak?

Yes, a fill valve can cause the toilet to leak. It breaks over time and starts letting the water out through hairline cracks and holes. That’s why you need to replace a leaking fill valve in your toilet. 

How do you know that your fill valve is bad?

You know that your fill valve is bad because you see water leaking from the bottom-left part of the tank. It’s a sign that the valve is broken, so it doesn’t sit tightly against the tank floor. As a result, you’ll notice puddles under the tank.

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