Leaky Faucet: DIY or Call a Plumber?
Which faucet leaks you can fix yourself in 30 minutes versus which ones need a plumber. Diagnostic guide, common faucet types, and when 'just replace it' is the right call.
A leaky faucet is one of the few plumbing problems most homeowners can actually fix themselves with $10 of parts and an hour of work. Some of them, anyway. The trick is knowing which leaks are the easy DIY ones and which are signs you should just call a plumber. Here's the diagnostic.
Step 1: Identify your faucet type
Most residential faucets fall into four categories: compression (oldest, two separate hot and cold handles that you twist closed), ball (single handle with a ball assembly under the cap), cartridge (single handle with a cartridge that slides up and down), and ceramic disc (most modern single-handle, very durable). The fix differs for each.
Easy DIY: dripping spout on a compression faucet
Almost always a worn rubber washer at the base of the stem. $2 of parts. Turn off the supply valves under the sink, unscrew the handle, remove the stem, replace the washer at the bottom, reassemble. 30 minutes. The hardest part is getting old stems out without breaking them.
Easy DIY: dripping spout on a cartridge faucet
Worn cartridge. Replacement cartridge: $20-50 from the faucet manufacturer. Turn off supplies, remove handle, pull old cartridge, slide in new one, reassemble. Make sure to get the exact replacement for your faucet brand and model — they're not universal.
Medium difficulty: ball faucet repair
More parts: ball, springs, valve seats, O-rings. Repair kit: $15-30. The fiddly part is keeping the small springs and seats organized during reassembly. Doable but not for the impatient.
Call a plumber: leaking from the base of the faucet (not the spout)
If water is coming up around where the faucet attaches to the sink (not dripping from the spout), the O-rings or seal under the faucet body have failed. Often easier to just replace the whole faucet at this point. Call a plumber or replace yourself if comfortable.
Call a plumber: leaking under the sink
If you see water under the sink, the leak isn't from the faucet itself — it's from supply lines, shutoff valves, drain tailpiece, or trap. Each has different fixes. Worth a service call to diagnose properly, especially if the leak is intermittent (water damage adds up).
Call a plumber: any leak on a tub or shower valve
Shower and tub valves are inside the wall. Repair almost always involves opening the wall (or the access panel if you have one), shutting off whole-house water, working in tight space, and reassembling the wall when done. Cheap repair, hard access. Worth a plumber for most homeowners.
When to just replace the whole faucet
If the faucet is more than 15 years old, repeated repairs are diminishing returns. Modern faucets are more efficient (low-flow aerators), better engineered (ceramic disc lasts decades), and often cheaper than the cumulative cost of repair parts. New mid-range kitchen or bathroom faucet: $100-250. Install (DIY): 1-2 hours; (plumber): $200-350.
Frequently Asked Questions
How much does a plumber charge to fix a leaky faucet?
Typically $175-$300 for a basic service call plus repair. If the faucet needs replacement and you supply the new one: $250-400. If we supply: $400-600 depending on faucet.
Why does my faucet drip even after I replaced the washer?
Probably worn valve seat — the brass surface the washer presses against can corrode and pit. You can re-grind it with a valve seat tool ($15) or replace the seat. If it's an old faucet, often easier to just replace the faucet.
Can a leaky faucet really increase my water bill?
Yes. A faucet dripping once per second wastes about 5 gallons per day = ~150 gallons per month. Not huge on its own but at $5-8 per thousand gallons in Greater Boston, it adds up over years. Plus the wear on fixtures.
What about the faucet that drips only when you first turn it off?
Normal residual drainage from the spout. If it continues dripping for 30+ seconds, that's a leak. A few seconds of trailing drip is just water draining.
Why does my faucet make a hammering sound when I shut it off?
Water hammer — the supply lines aren't restrained well and shock when flow stops suddenly. Add water hammer arrestors at the supply connections, $30-60 in parts.
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