Why a tub faucet drips
Behind the handle sits a valve that opens and closes the water. In older two-handle tubs that valve is a rubber washer pressed against a metal seat. Each time you turn the handle, the washer squeezes against the seat. Over the years the rubber flattens and hardens, and water slips past it.
Newer single-handle tubs use a cartridge instead. A cartridge is a plastic or brass cylinder with rubber seals and slots that line up to mix hot and cold. When the seals wear or minerals collect in the slots, the faucet drips, sticks or delivers uneven temperature.
A drip from the spout when the water is off means the valve is not sealing. A drip from behind the handle means a seal or packing nut has worn. Knowing which one you have shortens the repair, so tell the dispatcher where the water appears.
Symptoms and likely causes
| What you see | Likely cause | Usual repair |
|---|---|---|
| Spout drips when off | Worn washer, seat or cartridge seals | Replace the washer or cartridge |
| Handle leaks at the base | Worn packing or O-ring | Replace the packing or O-rings |
| Handle is stiff or gritty | Mineral scale on the cartridge | Clean or replace the cartridge |
| Water stays lukewarm | Cartridge stuck or mixing valve worn | Replace the cartridge or valve |
| Shower head weak, spout strong | Diverter worn or clogged | Clean or replace the diverter |
| Wall is damp or stained | Leak behind the tile | Plumber inspects the valve and supply lines |
Hard water leaves its mark inside the valve
Minerals are the quiet cause of many stiff handles. When water sits in a cartridge, calcium and magnesium dry out as a white crust on the moving parts. The crust grinds against the seals, and the handle gets harder to turn. A faucet with this kind of buildup often looks fine from the outside.
A water softener or filter slows the buildup, and the water softener and filtration page explains how those systems work. Replacing a scaled cartridge is a routine repair.
What you can check before you call
- Look at where the water appears: spout, handle base or the wall below.
- Run the shower and note whether the tub spout also leaks while the shower is on.
- Check the ceiling or wall on the other side of the tub for a stain.
- Try the handle at hot, then cold, and note any stiffness or grinding.
- Photograph the handle so the plumber can match the brand.
You can shut off the water to the house at the main valve if the leak is heavy. Most tubs have no separate shutoff in reach, which is why a stuck valve inside the wall deserves a call rather than a wrench.
When a drip is more than a drip
A faucet drip is a small leak, but a leak inside the wall is different. Water from a corroded supply pipe or a failed solder joint can soak drywall for weeks before a stain shows. If the wall around the tub feels soft, if tile grout is cracking or if the water bill climbs with no change in use, ask the plumber to check the pipes behind the faucet.
A hidden leak is the job of leak detection, which finds a leak without tearing open the wall first.
Faucet dripping or tub valve stuck?
Call the 24/7 line. A dispatcher schedules a licensed plumber and you hear the price before work starts.
Repair or replace the whole valve?
Many tub faucets can be fixed by replacing only the washer or cartridge. If the valve body is corroded, if parts are no longer made or if the handles are loose in the wall, replacing the whole valve is the longer-lasting fix. That job opens the wall from the back or the front and is more involved.
A plumber compares both options on site and explains the difference before starting. The faucet repair page covers sink and kitchen faucets as well.
Why a wrong fix makes things worse
Overtightening a handle screw cracks plastic parts and can strip the brass stem. Forcing a stuck handle can snap the cartridge stem inside the wall, which turns a ten-minute repair into a wall opening. Mixing parts from different brands is another common cause of repeat leaks, because seals and stems differ in small ways that matter.
If a part is stuck, stop, shut off the water and call. A plumber has pullers made for stuck cartridges.
How a plumber approaches the job
The plumber starts by shutting off the water and opening the handle trim to see what is inside. Photos of the old cartridge or stem help match a replacement. If the part is stocked, the swap is quick. If it is a discontinued style, the plumber may offer a universal repair kit or a full valve replacement.
After the repair, they run the tub at hot, cold and in between, and check the shower diverter. A short test run catches a leaking seal before the trim goes back on.
Keeping a tub faucet working longer
- Turn handles gently and do not force them past the stop.
- Clean the spout and shower head with a mild vinegar solution to dissolve scale.
- Fix small drips early, since a dripping seat wears faster as water cuts across it.
- Ask the plumber to note the brand and model after any repair for future parts.
Tub faucets and Sanger housing
Sanger's housing element reports that about 53 percent of homes in the city are more than 30 years old and about 29 percent are more than 50 years old. A tub valve in an older home may be a washer style that has been repaired before, and some are no longer stocked in standard form.
The city's 2024 water quality report lists average hardness of 145.5 ppm, with test results from not detected up to 330 ppm across the city's wells. Moderately hard water leaves scale in cartridges, so a stiff handle in Sanger is often a scale problem. Neighbors in Reedley and Selma see similar valley conditions.
Frequently asked questions
Not by itself. A slow drip can wait a day or two. Call right away if water is running and will not stop, or if you see water coming through a ceiling below.
A cartridge or washer swap is often done in under an hour when the part is available. A valve replacement takes longer because the wall may need to be opened. The plumber gives you the scope before work begins.
Mineral scale is the usual reason. Sanger's well water averaged 145.5 ppm hardness in the 2024 report, and the minerals build up on cartridges over time.
Only if it is cracked, loose or worn smooth. A cartridge repair does not require a new handle trim, though matching handles can look better together.