How to Fix a Leaking Toilet Shut-off Valve

A simple, white ceramic toilet in a bathroom painted orange.
  • 2-4 hours
  • Intermediate
  • 0-70
What You'll Need
Small plastic tub or any small container
Adjustable wrench
Slip joint pliers
Masking tape or protective tape
Clean rag or washcloth

The most common problem for a toilet shut-off valve is that it can develop a leak. Dripping shut-off valves can leave puddles of water on the bathroom floor which can ruin the flooring, make the room look dirty, destroy bathroom furniture, cause mold and mildew to grow, and run up your water bill. Leaking is caused by loose packing nuts on these valves. In some cases, this may also be caused by minerals deposits on the washers. A leaking shut-off valve doesn’t necessarily mean it always needs replacement. Follow the steps below for simple solutions to this issue before you engage in most costly repairs.

Step 1 – Tighten the Valve

The easiest solutions are best to try first, so start by giving the valve an adjustment to see if it solves your problem. Put a plastic tub under the leaking valve to reduce the water spillage on the floor while you work. Then, fit an adjustable wrench onto the nut of the shut-off valve and turn it counter-clockwise at 1/8 to 1/4 turn at a time. This will tighten the packing nut and may stop the drip.

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Step 2 – Prepare to Take it Apart

If the leaking doesn’t stop, you'll need to just remove the nut to get to the washers within. But first, you need to protect your bathroom and your equipment. Wrap the slip joint pliers' jaws in masking tape to protect your shut-off valve from any scratches caused by the sharp edges. Next, shut off the main water supply to the toilet, and detach and drain the pipes using a wrench or pliers. The small plastic tub will catch the water from the pipes to avoid spillage.

Step 3 – Remove the Nut

Get a hold of the shut-off valve and begin to take it apart. Take out the screw from the handle of the valve and untwist the packing nut. Remove the threaded valve system; when you do this, remember the position of the neoprene washers so that you can easily put them back together later, taking a picture of the set up if needed.

Step 4 – Clean the Washers

Take the neoprene washers and remove any mineral deposits by using a clean rag. While scrubbing, work them constantly until they are flexible once again.

Step 5 – Reassemble the Valve

Following your picture or your memory, start putting the shut-off valve back together. Make sure neoprene washers are positioned properly otherwise you will make more problems later.

Once again, tighten the packing nut 1/8 to 1/4 turn at a time using the wrench. Do not use plumber's putty or you might have a hard time fixing the shut-off valve in the future. Also make sure you don’t over tighten the nuts because it might damage the valve.

Step 6 – Turn On Water and Check for Leaks

Turn the water from the main back on, and watch for leaks as the line is being filled. If you see that the valves are still leaking, then its time to replace the shut-off valve entirely.

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