What to Do When the Toilet Shut-Off Valve Won’t Shut Off

I once tried replacing a toilet tank without closing the shutoff valve.

Things didn’t work out so well, to say the least.

If you plan on doing any kind of work on or around the toilet — and you want to avoid a bathroom disaster — make sure to shut off the water supply first.

But what happens when you can’t shut off the valve because it’s too old or rusty? In this case, you’ll have to react quickly. After all, you don’t want to think about the valve the next time your toilet starts leaking with waste still in the bowl.

You have two options: fix the shut-off valve, or replace it with a new one.

How Do You Know the Shut-Off Valve Isn’t Working?

There are three main reasons why your toilet shut-off valve may not be closing: 

• It’s stuck because it’s old and covered with dirt
• It’s turning only partially because it’s rusty
• The valve is leaking because it’s broken or damaged

In each case, there are ways to replace a valve, or install a new valve completely.

How to Repair a Malfunctioning Toilet Shut-Off Valve

The first task is to try and repair the existing fill valve. It’s much easier than unclogging a toilet, so don’t be scared of doing it yourself.

Step 1: Wiggle the Valve Back and Forth

Gradually move the valve clockwise and counterclockwise to loosen it up until it starts turning smoothly. You should now be able to shut off the toilet shutoff valve. 

If your fill valve is being extra stubborn and this solution doesn’t work, hop on to the next section.

Step 2: Tighten the Central Screw

Hold the shutoff valve with a pair of pliers and tighten the central screw — it’s a focal point that keeps the entire structure together, and so it needs to stay firm.

Step 3: Loosen the Valve With Hot Water

Cold metal elements are stiff and difficult to move without breaking. That’s why you need to soften them with some heat. 

Use a small bucket filled with hot water and place a cloth in it. When it’s soaking wet, put the hot cloth onto the valve — this will loosen up the cold water line.

Use rubber gloves when doing this — you don’t want to burn your hands. Then, leave the cloth on the valve for a couple of minutes, which is enough time for the heat to transfer to the valve and soften it. 

Alternatively, you can use a hairdryer to heat up the valve. 

Step 4: Use a Spray 

You can also spray the shutoff valve with a lubricant. We recommend WD-40 because it doesn’t affect the rubber washer supporting the shutoff valve. After spraying, leave the lubricant for 10 minutes before attempting to turn the valve again.

How to Replace a Broken Toilet Valve

Sometimes it’s just not possible to fix the valve, so you’ll need to replace it. Here’s how you can:

Step 1: Close the Main Water Supply

You need to find the main water supply shutoff valve and seal it so that no water can flow out. The majority are hiding in the basement, in the laundry room, or under the kitchen sink.

Step 2: Remove Excess Water From the Pipes

You now need to drain the supply line before removing the toilet valve. It’s a necessary step because it stops water from overflowing onto your bathroom floor from the drain, pipes, and toilet tank. 

Turn on a faucet that is positioned lower than the toilet valve you want to replace. This procedure allows excess water to flow down the pipes above it, including the pipe supplying water to your toilet tank.

Step 3: Close the Toilet Supply Line

You also need to close the toilet supply line, AKA a hose transferring water from your toilet to the shutoff valve. Put a bucket directly under the shut off valve to collect water coming out of the pipe. 

Take off the bolt that connects the supply line to the valve using a crescent wrench. Then, pull out the line from the valve.

Step 4: Remove the Existing Shut-Off Valve

There are two types of valve connections, and each demands a different removal strategy.

1. Valves With Compression Joints

If you’re working with a compression joint, remove the bolt connecting the pipe to the current valve with a crescent wrench while holding the pipe in place with pliers. 

The pliers will keep the pipe from turning and breaking as you tighten the bolt. As soon as you do it, you can remove the old shut off valve.

2. Valves With Sweated Copper Pipes

If you’re facing a sweated copper pipe and joints, remove the old valve and cut away any debris with a tube cutter. Remove the valve by twisting the pipe cutter and cutting through the metal. 

Remember to leave as much of the pipe from the wall as possible — it will make room for the new fitting. Leaving the pipe is important, because a longer piece will make it easier to fit in the new valve. 

Step 5: Install a New Valve

Now you should place a compression nut on the toilet pipe and attach the new shutoff valve to the compression ring. Use a pair of crescent wrenches to hold and screw the compression nut and the valve stem’s threads. 

Remember that the valve’s outlet must be looking upward because it needs to connect to the supply line.

Step 6: Bring Back the Toilet Supply Line

Step number six is to attach the toilet supply line to the valve. If the new valve does not align with the water supply hose, you will need to loosen and adjust the nut.

Step 7: Open the Main Water Supply

Finally, you can go back to the basement of wherever the main water supply valve is and turn it on again. Your shutoff valve should now be working properly.

Tools You’ll Need to Fix Toilet Shut-Off Valve

Fixing or replacing a shutoff valve requires only the basic tools.

Here is what it takes to repair a shutoff valve. These tools and materials are not expensive, and you probably already have them at home or in your garage: 

• A cloth
• A pair of gloves
• A screwdriver
• A spray lubricant
• A bowl of hot water

Here are the tools you’ll need to replace a shutoff valve. You may need to purchase some of these items, but they are affordable:

• Craftsman slip-joint pliers
• A screwdriver
• A tube cutter
• A bucket
• A couple of adjustable crescent wrenches
• A pair of gloves
• A new shutoff valve

The Bottom Line

If you’re unable to close your toilet’s shutoff valve, make sure to turn off the main shutoff valve first. After that, you can try two things:

• Fixing the existing toilet valve
• Replace the worn-out valve with a new valve

Follow our step-by-step instructions, and don’t forget to read other articles on Bomisch — we have more DIY tips for you!

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