Likely cause: worn spout o-rings

Why this happens

Moen's guidance for a faucet that leaks between the spout and the handle points at a scratched or torn o-ring on the cartridge or spout. Water gets past the damaged ring only when the faucet is on and the spout is under pressure. Moen adds that on single-handle faucets with a side spray, the diverter can be involved too, and without a side spray it comes down to the o-rings.

How to fix it

1. Shut off both stops under the sink and open the faucet to release pressure. Close the drain so small parts cannot fall in.
2. Remove the handle. Look for a set screw under a cap or on the side of the handle.
3. Lift off the spout and look at the o-rings on the faucet body and on the cartridge. Replace any that are flattened, nicked or cracked.
4. Coat the new o-rings with silicone grease only. Moen warns against plumber's grade faucet grease, silicone sprays or any lubricant that may contain petroleum. Moen's own silicone grease is part 99915.
5. Reinstall the spout and handle, reopen the stops slowly, and run the faucet while you watch the base.
6. If the cartridge o-rings are torn, or the leak returns, replace the cartridge with one matched to your faucet.

When to stop. If the spout will not lift off by hand, or the stops under the sink will not close, stop before you force anything.

The part that fixes it

The repair kit and cartridges fit single-handle Moen faucets that use the 1225 cartridge. O-ring kits for other brands are faucet-specific.

Not sure which part you have? Pull the old one and match it by brand, length and broach on Stems & Cartridges, an identification index of faucet stems and cartridges by part number.

Start this troubleshooter over

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