That steady tick… tick… tick from the tub spout at 2 a.m. isn’t just annoying, it’s money running down the drain, roughly 3,000 gallons a year for a faucet dripping once per second. A bathtub faucet dripping when off almost always comes down to a worn internal part that can no longer make a watertight seal against the water pressure behind it. The specific part depends on what kind of valve you have, but in most cases the repair is a 30-to-60-minute job with basic tools and a part that costs less than $20. Here’s how to find the cause and fix it for good.
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Why a Closed Faucet Still Drips
When you turn the handle off, an internal component, a cartridge, a rubber washer, or a ceramic disc, presses against a seat to block the flowing water. Over time that sealing surface wears, cracks, or gets chewed up by mineral deposits and grit in the water. Once the seal isn’t perfect, pressurized water finds the gap and forces its way through, dripping out the tub spout. The drip happens when the faucet is “off” precisely because that’s when the seal is supposed to be doing its hardest work against full line pressure.
Before you buy parts, identify your valve type. A single-handle tub faucet uses a cartridge or a ball assembly. A two-handle or three-handle setup (separate hot and cold) uses compression washers or ceramic-disc stems. This distinction determines which parts you’ll replace.
The Usual Suspect: A Worn Cartridge
On modern single-handle tub and shower faucets, the cartridge is the number-one cause of drips. Brands like Moen, Delta, and Kohler each use their own cartridge design, and after years of use the internal seals harden or the plastic body cracks. The fix is a straight swap. Shut off the water, pop the handle cover, remove the handle screw, pull the retaining clip, and extract the old cartridge with pliers or the brand’s puller tool.
Take the old cartridge to the store or match it by faucet brand and model. A Moen 1225 cartridge runs about $15 to $25; a Delta RP series cartridge is similar. Lubricate the new one with silicone faucet grease, seat it in the same orientation, and reassemble. Nine out of ten single-handle drips end right here.
Two-Handle Faucets: Washers and Seats
Older compression-style faucets, the kind with separate hot and cold handles you screw down tight, drip because the rubber washer at the bottom of the stem has flattened or torn. This is the classic, cheapest repair in plumbing. Shut off the water, remove the handle and the packing nut, and unthread the stem. At the bottom you’ll find a brass screw holding a small rubber washer. Replace that washer (a variety pack is $4) with an exact match.
While the stem is out, feel the brass seat inside the valve body with a fingertip. If it’s pitted or rough, a new washer will just wear out again. Either dress the seat with a seat-grinding tool or replace it with a seat wrench if it’s the removable type. A rough seat is the reason so many people replace a washer and the drip comes back a month later.
Ceramic Disc and Ball Valves
Some faucets use ceramic-disc cartridges, which are extremely durable but can still fail from mineral scale or grit scoring the polished discs. You’ll usually replace the whole disc cartridge rather than rebuild it. Ball-type faucets, common on certain older single-handle models, drip when the springs and rubber seats under the ball wear out; a repair kit with new springs, seats, and O-rings runs about $10 to $15 and includes the small parts you need.
For any of these, shut off the water and open the faucet to relieve pressure before disassembly. Lay the parts out in order as you remove them; reassembling in the wrong sequence is the most common DIY mistake.
Don’t Overlook the Diverter and O-Rings
If water only drips from the tub spout while the shower is running, the problem isn’t the handle at all, it’s the diverter inside the spout that’s supposed to send water up to the showerhead. A worn diverter lets water leak back out the tub spout. In that case, the fix is often replacing the entire tub spout, a $15 to $30 part that unscrews or unclamps from the wall pipe. Worn O-rings on a cartridge can also cause weeping around the base of the handle rather than a spout drip, so match the symptom to the part.
Step-by-Step: Stopping the Drip
- Shut off the water. Use the shut-offs behind an access panel if present, or the main.
- Open the faucet to drain residual water and relieve pressure.
- Plug the tub drain so you don’t lose small screws.
- Remove the handle and expose the cartridge or stem.
- Extract the worn part and match it exactly by brand and model.
- Inspect the seat and O-rings while you’re in there; replace anything worn.
- Grease the new part with silicone, reassemble, and slowly restore water.
- Test hot and cold, then check for drips over the next 24 hours.
How Much a Dripping Faucet Really Costs
It’s tempting to ignore a slow drip, but the math is sobering. A faucet dripping once per second wastes roughly 3,000 gallons a year, and a faster drip or a small steady stream can waste far more. On a metered water and sewer bill, that’s real money, often $20 to $70 a year for a single faucet, and if it’s the hot side dripping, you’re also paying to heat water that goes straight down the drain. Beyond the utility cost, a chronic drip stains the tub with mineral deposits and can slowly erode the finish. Set against a $4 washer or a $20 cartridge and an hour of your time, the repair pays for itself in a matter of weeks.
There’s a comfort cost too. A dripping tub spout that shares a valve with the shower can also mean your shower loses pressure, since water escapes the spout instead of going up to the head. Fixing the drip often restores shower performance as a bonus.
Water damage is the hidden expense people forget. A drip that runs down the wall behind an old spout, or that keeps the tub surround perpetually damp, can feed mold and eventually rot the substrate behind the tile. What starts as a minor annoyance becomes a $500-plus tile repair if you let it run for a year or two. That’s the real argument for fixing a drip the week you notice it rather than living with the sound, the cheap part now prevents an expensive problem later.
Preventing Future Drips
A few habits extend the life of your repair and delay the next one. Don’t crank the handle shut with all your strength, especially on compression faucets; over-tightening crushes the washer and grinds the seat, guaranteeing a faster failure. Snug is enough. If you live in a hard-water area, the mineral scale that chews up cartridges and seats builds fast, so consider a whole-house water softener or at least periodic descaling of the aerator and accessible parts. When you do a repair, replace all the wear parts you can access, washer, O-rings, and springs, rather than just the one that failed, since they’ve all aged together. And keep a matching cartridge or washer kit on hand; the next drip always seems to start on a Sunday night when the hardware store is closed.
When to Call a Plumber
Most cases of a bathtub faucet dripping when off are firmly in DIY territory. Call a pro if the valve body itself is corroded and the cartridge won’t budge, if you have no shut-offs and are uneasy killing the main, or if you have an old three-handle setup buried behind tile that may need the whole valve replaced. A plumber’s visit typically runs $150 to $350 depending on the valve, still cheaper than the water bill and potential water damage from ignoring a persistent drip. Fix it early and that midnight tick disappears for years.
