Where the leak is tells you the part
| Where it leaks | Likely part | Fix |
|---|---|---|
| From the spout when off | Cartridge, washer or seat | Replace the part |
| Around the handle | O-ring or packing | Replace the seal |
| At the base of the spout | Spout O-rings | Replace the O-rings |
| Under the sink | Supply line, shutoff or drain | Replace the part or tighten |
| Low flow, no leak | Clogged aerator | Clean the aerator |
Before you start, close the shutoff valves under the sink. If they are stuck or do not hold, close the main house valve. Put a towel in the sink so no small part falls down the drain.
A simple repair order
- Identify the type. Look at the handle. Two handles are usually compression or cartridge. One handle is cartridge, ball or ceramic disc.
- Take it apart. Pop off the handle cap, remove the screw and lift the handle. Keep the parts in order.
- Pull the worn part. Take the cartridge, washer or seat to a hardware store and match it exactly.
- Reassemble and test. Open the shutoff slowly and check for drips at the spout, handle and base.
A faucet with a metal body and a good finish is worth repairing. The parts are inexpensive and the job is within reach for many owners.
Leak getting worse or hard to reach? Call for a plumber.
Call (650) 860-1670Repair or replace
Replace when the finish is pitted or flaking, when mineral buildup has damaged the body, when the parts are discontinued or when you want a different style. A faucet that has been repaired several times is also a candidate. The labor to fix it a fourth time can match the cost of a new one.
If the leak is under the sink, the faucet may be fine and a worn shutoff valve or supply line is the cause. Replacing those at the same time saves a second visit. Faucet repair covers what a plumber checks.
What a drip costs you
A faucet that drips once a second adds up. Over a month it can waste a surprising amount of water, and the cost shows on the bill. Hot water drips cost twice because you also pay to heat what is wasted.
A drip is also a sign that a seal is failing. Waiting can let minerals scar the seat, which turns a cheap fix into a replacement.
Know your faucet type before you buy parts
Compression faucets
These have separate hot and cold handles and use a rubber washer pressed against a seat. The washer wears, and the fix is to replace the washer and sometimes the seat. They are the simplest to repair.
Cartridge faucets
A cartridge slides into the body and controls flow and mix. When it wears, the spout drips or the handle feels loose. The fix is a new cartridge of the same make and model.
Ball and ceramic disc faucets
These use a rotating ball or sealed discs. They last longer, but when they fail the repair usually means a kit of seats, springs and O-rings, or a new cartridge. A plumber can tell you which you have.
Tools and parts worth having on hand
Most faucet repairs need an adjustable wrench, a screwdriver set, a hex key set, plumber's grease and a flashlight. A small container keeps screws from rolling away. Take photos as you disassemble so you can put things back in order.
Buy the repair part only after you have the old one in hand, and match it exactly. A close fit is not a fit. If the model is old and the part is not available, a replacement faucet is the better path, and the plumber can install it with new supply lines and shutoff valves.
When the leak is not the faucet at all
Water under a sink often gets blamed on the faucet when it comes from elsewhere. Supply lines can drip at the connections, shutoff valves can weep around their stems and drain traps can leak at their slip joints. A disposal or a dishwasher hose can also drip into the same cabinet.
Dry everything, then run water with a dry paper towel under each connection in turn. The towel shows which joint is the source. A weeping valve or a cracked supply line is cheap to replace, and fixing the right part the first time saves a return visit.
What comes out of a Mountain View tap
The City of Mountain View reports that its 2024 inventory found no lead service lines. That is a statement about the pipe from the main to the meter, not about the fixtures and solder inside an older house. If you replace a faucet in an older home, choose a lead-free fixture and ask the plumber about the supply lines.
The City also offers a free do-it-yourself leak detection kit at 408-630-2554, and its conservation page says a one-time bill reduction may be available after a leak is fixed. Keep your receipt. If the same drip appears in a Los Altos home, the City of Los Altos or Cal Water would be the contact for billing questions.
If the leak is bigger than a drip, the service area page shows where we dispatch around the clock.
If you hire a plumber for the swap, supply stops and the trap under the sink are fitted to the California Plumbing Code rather than left as they were.
Questions about this topic
Can I fix a leaking faucet myself?
Often yes. Shut off the supply, identify the type, replace the failed part and test. If the valves are stuck or the leak is under the sink, call a plumber.
Why is my faucet leaking at the base?
The O-rings around the spout have likely worn. They are inexpensive and easy to replace.
How do I know if the leak is the faucet or the pipe?
Dry the area, put a paper towel under the sink and watch. A drip from the faucet line means the faucet. A wet towel under the pipes means a supply line or valve.
Is a dripping faucet worth fixing?
Yes. It wastes water and the problem tends to get worse.
What does the City of Mountain View offer for leak checks?
A free do-it-yourself leak detection kit is available by phone at 408-630-2554, per the City's conservation page.