A bathtub faucet that drips all night is more than an annoyance. A steady drip wastes over 200 gallons a month, stains the tub, and quietly inflates your water bill. The good news: in most cases the fix is a $15–$30 cartridge or washer and about 30 minutes of your time.
Here is how to diagnose your faucet type and fix the drip — plus the warning signs that mean the problem is bigger than a washer.
1. 💧 What a Drip Costs You
One drip per second adds up to roughly 3,000 gallons a year. At average US water rates that is real money — and if you are on a septic system or pay sewer charges based on water use, you are paying twice for every wasted drop.
A hot-side drip costs even more, because you are also paying to heat water nobody uses.
2. 🔍 Identify Your Faucet Type
- Single-handle (cartridge): one lever controls temperature and flow. The cartridge inside wears out over 5–10 years.
- Two-handle (compression): separate hot and cold knobs. Rubber washers at the base of each stem compress to stop flow — and washers are the part that fails.
Knowing your type before you start saves a trip back to the hardware store. If you can see a brand name (Moen, Delta, Kohler) on the trim, note it — cartridges are brand-specific.
3. 🛑 Shut Off the Water First
Find the shutoff valves for the tub — often an access panel behind the tub wall or in a closet. No dedicated valves? Shut off the home's main water supply. Then open the faucet to drain residual pressure and confirm the water is truly off before you disassemble anything.
Stuff a rag in the drain so small screws and clips do not disappear into it. Ask anyone who has fished a cartridge clip out of a P-trap: this step matters.
4. 🔧 The Fix: Cartridge or Washer Swap
For single-handle faucets: remove the handle (usually one Allen screw), pull the retaining clip, and slide the old cartridge straight out. Note its orientation, then slide the new one in exactly the same way. Reassemble in reverse order.
For two-handle faucets: unscrew the stem, replace the washer and O-ring at its base, and apply plumber's grease to the threads before reinstalling. Take the old washer to the store to match the size — close enough is not good enough with washers.
5. ⚠️ When Corrosion Wins: Call a Plumber
Stop and call a professional if: the valve body behind the wall is green with corrosion, the cartridge is seized and will not budge, water leaks from behind the wall when you test, or the faucet is so old that replacement parts no longer exist.
Forcing a corroded valve can crack the pipe inside the wall and turn a $30 DIY into a drywall-and-plumbing repair. A plumber can also tell you whether the fixture is worth saving — our bathroom remodel mistakes guide covers when replacement beats repair.
6. 💵 What a Plumber Charges for This
A straightforward tub faucet repair typically runs $150–$300 including parts, depending on your market. If the valve needs replacing inside the wall, expect more — see our plumber cost guide for current Knoxville pricing context.
Weigh that against your time, the parts run, and the risk of a stuck valve. For many homeowners the pro visit is the cheaper option once everything is counted.
Frequently Asked Questions
Why does my bathtub faucet drip only at night?
It probably drips all the time — you just notice it at night when the house is quiet. Thermal expansion can also make drips slightly worse as pipes cool overnight.
Can a dripping faucet increase my water bill a lot?
Yes. A fast drip wastes 3,000+ gallons a year, and a hot-side drip wastes energy too. Fixing it usually pays for itself within a month or two.
Do I need to turn off the main water to fix a tub faucet?
Only if there are no dedicated shutoff valves for the tub. Check for an access panel behind the tub wall first — many homes have individual stops there.
How do I know what cartridge my faucet needs?
Look for the brand name on the trim plate or handle. If there is none, remove the old cartridge and bring it to the hardware store — staff can usually match it, or you can match it to the manufacturer's parts diagram online.
Drip Driving You Crazy?
If the cartridge swap didn't stop the drip — or you'd rather not gamble with a corroded valve inside the wall — let a pro handle it. Call Best Value Plumb and we'll connect you with a local plumber in Mary Esther, Oakland Park, or Knoxville who can fix it right the first time.
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