Hammond Re-Engineered DIY Guides · No. 8
Stop an Under-Sink Leak
Trap, Supply Line, Shutoff — In That Order
Four places an under-sink leak comes from, ranked by how cheap they are to fix. Work down the list and you'll stop the drip in an afternoon.
About This Guide
Four places. Ninety minutes. Eight dollars.
An under-sink leak is one of four specific connections, and each one is under ten dollars to fix if you diagnose before you replace.
This book walks the four, in order of probability:
- **P-trap slip-nuts** — loose or worn washers. Fix: tighten, or
- \$3 washer pack.
- **Supply-line connection** — at the shutoff or at the faucet.
- Fix: tighten, replace washer, or \$8 new line.
- **Shutoff valve body** — a valve weeping from the stem or the
- body. Fix: valve replacement, \$15.
- **Drain tailpiece** — the vertical pipe from the drain to the
- trap, cracked or loose. Fix: \$5 replacement.
For each: how to tell which it is, how to fix it, and how to leak-test so you don't finish the job on Saturday and find a new puddle on Sunday morning.
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