A dripping bathtub faucet is almost always a worn internal part: a rubber washer and seat in a two-handle tub, or a cartridge in a one-handle tub. Drips from the spout point at the valve internals. Water around the handle points at a loose nut or worn seal. Water sliding down the wall points at the pipe behind the tile, which is not a DIY fix. Below, we separate the three and give the repair for each. Our hub on faucets, sinks, showers and disposals covers neighboring problems.
Where is the water coming from?
Watch the faucet for a few minutes with the tub dry. Water from the spout when everything is off means a worn washer, seat or cartridge. Water beading around the base of a handle means a loose packing nut or a worn stem seal. Water that only appears when you pull the diverter means the diverter is failing. Water on the wall or ceiling below is a leak inside the wall.
This sorting step saves money, because bathroom fixtures vary and a wrong guess means the wrong part. People often replace a whole faucet for a diverter that costs a few dollars, or tighten a handle nut when the real fault is a cartridge. Use this table to pick your path.
| What you see | Most likely cause | Fix |
|---|---|---|
| Drip from spout, one-handle tub | Worn cartridge or seals | Replace cartridge |
| Drip from spout, two-handle tub | Worn washer or seat (compression type) | Replace washer, maybe the seat |
| Leak at the base of a handle | Packing nut or stem seal | Tighten, repack or replace stem |
| Spout dribbles while the shower runs | Failing diverter | Replace diverter or spout |
| Stains or dampness on the wall or ceiling below | Leak inside the wall | Call a plumber |
How do I stop a drip from a two-handle tub faucet?
Two-handle tub faucets often use compression valves: turning the handle presses a rubber washer onto a brass seat. Over time the washer hardens and the seat roughens, so the valve never fully seals. EPA WaterSense notes that worn faucet washers and gaskets frequently cause faucet leaks. The cure is a new washer, and sometimes a reseating tool or a new seat.
Shut the water off first. Many tubs have no local stop valves, so use the main house valve and open the tub tap to drain pressure. Pry the cap off the handle, remove the screw, pull the handle and the escutcheon, and unscrew the stem with a wrench. Take the stem to a hardware store to match the washer and the O-ring. Put it back, turn the water on slowly, and test.
If a new washer does not cure the drip, the seat inside the valve body is damaged. A seat wrench can remove and replace it. If the seat will not come out, or the handles are corroded to the stems, stop. That is where a plumber earns the visit.
How do I fix a leaky one-handle tub faucet?
A one-handle tub faucet uses a cartridge or a ball assembly, and one worn seal lets water past. The repair is to replace the cartridge. You need the exact part, so check the brand name stamped on the trim or inside the handle, or the model number from the original paperwork. A cartridge that is close but wrong will not seal.
Turn off the water, remove the handle cap and screw, then the handle and the trim plate. Many manufacturers put a clip or retaining nut over the cartridge. Pull the clip, pull the cartridge straight out, and note which direction it faced. Some brands recommend a puller tool for stubborn ones. Insert the new cartridge facing the same direction, grease the O-rings with plumber's silicone grease, and reassemble. Moen's support pages note that if hot and cold come out reversed, the cartridge is rotated 180 degrees and should be turned back.
Delta, Moen and other brands each use their own cartridge shapes, and their support pages show the exact removal steps. Because that shape varies, do not buy a "universal" cartridge without checking it against the old one.
Why does my tub spout drip after I switch from bath to shower?
The diverter is the part that sends water up the shower riser instead of out the spout. If water still dribbles from the spout during a shower, the diverter is not seating. On a tub spout with a pull-up knob on top, the spout itself is the diverter, and replacing the spout usually fixes it. Spouts either unscrew or are held by a small set screw underneath.
If the diverter is built into a two- or three-handle valve, the repair is a diverter cartridge or stem, similar to the repairs above. Hard water speeds the failure. LADWP's own figures show hardness ranging from roughly 5 to 17 grains per gallon in its service area, and its FAQ says hard water leaves mineral deposits in plumbing. Scale on a diverter keeps it from sealing.
Does a leaky tub faucet really waste that much water?
Yes, more than people expect. EPA WaterSense says a faucet that drips once per second wastes more than 3,000 gallons a year, enough for about 180 showers. Besides the water, a slow drip stains the porcelain and can mean the seal behind the wall is next to fail. In Los Angeles, where many homes are older, early repair is cheap.
If you see a high bill and cannot find a leak, check the tub spout, the toilets and the outdoor taps in that order. Our page on why a water bill climbs walks through the full check, including how to read your meter.
When should I call a plumber instead of fixing it myself?
Call a plumber when the leak is inside the wall, when handles or stems are corroded and will not come off, when new parts do not stop the drip, or when the valve body itself is cracked. Many older bathrooms have valves buried behind tile with no access panel, and replacing one means opening the wall.
Replacing the valve body also changes the plumbing. In California, work worth $over $1,000 once labor and materials are added, or work that needs a permit, requires a contractor with a C-36 plumbing license from the CSLB. A simple cartridge swap is under that line. A valve replacement behind tile may not be. A plumber will also check the shutoff valves while the wall is open.
If the leaking faucet is on a shower rather than a tub, see our page on fixing a leaky shower faucet. For the general method that applies to any dripping faucet, read how to fix a leaky faucet. To book a visit, ask for a written quote and we'll arrange a local plumber to come to you.
Common questions
How do I fix a dripping bathtub faucet without replacing it?
Replace the worn internal part rather than the whole faucet. In a two-handle tub that is the washer or seat. In a one-handle tub it is the cartridge. Both are inexpensive and take under an hour once the water is off and the handle is removed. Replace the whole faucet only if the valve body is cracked or the stems are corroded.
How do I fix a leaky Delta tub faucet?
Identify the series printed on the trim or the model number, then buy the matching Delta cartridge or repair kit. Shut off the water, remove the handle, bonnet and cartridge, and swap in the new one with fresh grease. Delta's support pages show the exact parts for each series, so match them before you buy.
Can I fix a leaky tub faucet without shutting off the water?
No. Always stop the supply before taking a cartridge or stem out. A tub valve is under full house pressure, and removing the part with the water on sends water everywhere. If the tub has no stop valves, close the main house valve, and open a faucet to drain the lines first.
How long does it take to fix a leaky bathtub faucet?
A cartridge or washer swap usually takes 30 to 60 minutes if the parts fit and the screws are not seized. Add time for a trip to the hardware store to match parts. A stuck stem, corroded trim or a missing access panel turns it into a longer job.
How much does a plumber charge to fix a leaking tub faucet?
It depends on whether the job is a cartridge swap or a valve replacement behind the wall. Simple repairs are usually priced close to a service call plus parts. For the range and what changes it, see faucet installation and replacement costs, and ask for a written quote.