How to Replace a Bathtub Faucet Valve (Single and Two Handle)

Disclosure: Some of the links in this article may be affiliate links, which can provide compensation to me at no cost to you. You can read our affiliate disclosure in our privacy policy.

If your bathtub faucet drips all night or the handle will not turn the water fully off, the problem is almost always inside the valve. The good news: you rarely need to tear open the wall. With a couple of screwdrivers, pliers and the right replacement part, you can fix it in under an hour.

Quick answer

To replace a bathtub faucet valve, turn off the water, remove the handle, then swap the worn part: the cartridge on a single handle faucet, or the washer and O-ring on the stem of a two handle faucet. Reassemble the handle and turn the water back on to test.

Key takeaways

Know your faucet: single handle faucets use a cartridge, two handle faucets usually use a stem with a washer.
Water off at the main: most tubs have no shutoff valve you can reach.
Match the part: the new cartridge must be made for your exact faucet.
Bag the small parts: retainer clips and screws disappear down drains fast.
The valve body rarely fails: replacing it behind the wall is a plumber's job.

Signs Your Bathtub Faucet Valve Needs Work

A faucet valve wears slowly, so the signs creep up on you. Watch for these:

Constant dripping from the spout even with the handle fully closed.
A handle that will not shut the water off or needs extra force to do it.
A stiff or grinding handle that is hard to turn.
Poor temperature control, where the mix jumps from hot to cold.
Water leaking around the handle rather than from the spout.

Which Type of Faucet Do You Have?

Most modern tubs

Single Handle Faucet

One lever or knob controls both flow and temperature. Inside, a cartridge does all the work. When it wears out, you replace the whole cartridge.

Older bathrooms

Two Handle Faucet

Separate hot and cold handles, each with its own stem. A rubber washer at the end of the stem closes the water off. A worn washer or O-ring is the usual cause of drips.

Safety first

Turn off the water before you remove any handle. Many bathtubs have no shutoff valve you can reach, so you may need to close the main water valve for the house. Open the tub faucet afterwards to drain the remaining water and pressure, and put a towel in the tub to protect it and catch dropped parts.

How to Replace a Single Handle Bathtub Faucet Valve

Tools and Materials

Phillips screwdriver
Small flathead screwdriver
Pliers
Plastic zip-top bag for small parts
Replacement cartridge made for your faucet
Cartridge puller (only if the cartridge is stuck)

Turn off the water
Close the shutoff or the main valve, then open the tub faucet to let the remaining water drain out.
Find the set screw and remove the handle
The set screw is usually under a decorative cap or on the underside of the handle. Pry the cap off with your small flathead screwdriver, remove the screw and pull the handle off. Remove the trim plate if it covers the valve.
Remove the retainer clip
Locate the retainer clip at the top of the valve cartridge. Pull it out with your screwdriver and put it straight into the plastic bag. I bag every small part as I go, so nothing gets lost while I work.
Pull out the old cartridge
Grip the cartridge stem with pliers and gently pull it straight out. If it will not budge, do not force it: a cartridge removal tool from your local hardware store will pull it out without damaging the valve body.
Insert the new cartridge
Your replacement must be a cartridge made for your specific bathtub faucet. Push it in with the same orientation as the old one, then put the retainer clip back from the bag.
Reassemble and test
Reinstall the trim, handle and set screw. Turn the water back on and check the hot and cold positions and that the spout stops dripping when you close the handle.

How to Fix a Two Handle Bathtub Faucet Valve

Tools and Materials

Phillips screwdriver
Flathead screwdriver
Pliers
Pipe wrench or deep socket for the bonnet nut
New washer of the same type and size
New O-ring
Petroleum jelly or plumber's grease

Turn off the water and remove the cap
Turn the water off at the main. With a flathead screwdriver, pop off the cap on the front of the handle, remove the screw behind it and pull the handle off.
Remove the stem
Loosen the bonnet nut, then turn the stem counterclockwise with pliers or a wrench until it comes out of the valve body.
Replace the old washer
At the end of the stem you will see a small screw holding the washer. Remove it and fit a new washer of exactly the same type. Give it a light coat of petroleum jelly before you put the screw back.
Replace the O-ring
Find the O-ring around the stem. Remove the old one and roll on a new one, also coated with a little petroleum jelly so it seats smoothly.
Put everything back in place
Install the stem (or a new stem if the old one is damaged), tighten the bonnet nut and reinstall the handle and cap. Turn the water on and check for drips.

When to Call a Plumber

Swapping a cartridge or a washer is a homeowner job. Replacing the valve body itself is not. That means opening the wall or the access panel, cutting pipe and often soldering, and in my experience it is easy to turn a small drip into a big leak.

Call a pro if the valve body is cracked, the threads are stripped, the stem will not come out after a cartridge puller, or water leaks behind the wall. If you would rather fix a leaky bathtub faucet without replacing parts first, start there.

Common Mistakes to Avoid

Buying a "close enough" cartridge: it will leak or not fit. Bring the old one to the store.
Forcing a stuck cartridge: you can damage the valve body. Use a puller.
Leaving the drain open: cover it before you start, clips and screws are tiny.
Skipping the grease: a dry O-ring or washer wears out faster.
Overtightening the bonnet nut: snug is enough, too tight can crack the parts.

FAQs

How do you remove a faucet handle without screws?

Look for a hidden set screw or a decorative cap. Pry the cap off gently with a small flathead screwdriver to reach the screw, then pull the handle straight off.

Why does my bathtub faucet keep running?

On a two handle faucet, an old, worn rubber washer is the usual cause. On a single handle faucet, a worn cartridge is the most likely culprit.

Do I need to replace the whole valve or just the cartridge?

In most cases, only the cartridge or the stem parts. The valve body behind the wall rarely fails, and replacing it means opening the wall and often soldering, which is a job for a plumber.

How do I find the right replacement cartridge?

Use one made for your specific faucet. Note the brand and model, or take the old cartridge to the hardware store to match it.

Most "bad valves" are really a worn cartridge or a tired washer. Shut off the water, remove the handle, swap the part with an exact match and reassemble. If the problem is behind the wall, stop there and call a plumber. And if your faucet is simply worn out, our best bathtub faucets guide can help you pick a replacement.