Why does my faucet leak from the base of the handle?

Water travels, so the puddle you see may not be where the leak starts. Moen says that "a handle leak can puddle onto the base plate (escutcheon) making it appear to be a leak at the base of the faucet," and gives a simple test: wrap a paper towel around the handle and turn on the faucet. A wet towel means the handle is the source. A dry towel with a wet base means the leak is lower, where the spout or body meets the deck.

Kohler splits it the same way. In its words, a leak "under the handle" is water leaking "from the area where the handle attaches to the faucet body," while a leak at the base of the spout shows up "from the area where the faucet base touches the escutcheon plate or countertop." Do the towel test first. It takes thirty seconds and keeps you from replacing the wrong part.

Kohler's troubleshooting pages tie the cause to the timing:

• Leaks only while the faucet is running. Kohler says dirt or debris has collected on the seals or O-rings, which stops them from sealing inside the faucet body. The fix is new seals or O-rings.
• Leaks after the faucet is off. Kohler says dirt and debris in the valve or cartridge keep it from controlling the flow. The fix is a new valve or cartridge, and on some models the spacer or check valve assembly too.

That split is the most useful thing you can learn before you open anything up. It also explains why a faucet can seep for months and then start spraying: the seal ages quietly, then lets go.

It can. The City of Phoenix reports total hardness of 10 to 17.6 grains per gallon in its water, and says hard water can cause "some types of scaling in pipes and water heaters, and on plumbing fixtures such as faucets and showerheads." Scale roughens the sliding surfaces on a cartridge and scours rubber O-rings as the handle moves. If you have a water softener, your faucet parts usually last longer. If you do not, expect to replace a cartridge or seals now and then. Our page on whether softeners work on Arizona hard water covers that decision.

The repair depends on the faucet style, and the maker's own parts diagram tells you the exact part. The steps are the same in outline:

1. 1Shut off the water. Close the angle stops under the sink by turning them clockwise, then open the faucet to drain it and prove the water is off. Our guide to shutting off water to a single fixture shows where those valves hide.
2. 2Plug the drain or lay a towel in the sink so a small screw or clip does not disappear.
3. 3Remove the handle. Look for a set screw (often a small hex screw under a cap or at the back), then lift the handle straight off. Our page on a loose faucet handle covers the screw types.
4. 4Pull the cartridge and compare it to the new one before you install it. Moen notes that its cartridges come in several types and "are not interchangeable with each other," so match the model, not just the brand.
5. 5Reassemble and test. Turn the water on slowly, run the faucet, then shut it off and watch for seepage. Pfister suggests letting the water run for a minute, turning it off, and checking whether the faucet still leaks.

If the towel stays dry and the water collects around the spout base, the culprit is a different set of parts. Moen's instructions depend on the faucet. For a bathroom single-handle or centerset faucet, remove and clean the aerator, rethread it, and replace the cartridge if the leak persists. For a kitchen faucet, Moen says to replace the O-rings, plus the diverter on a single-handle faucet with a side spray. Pullout and pulldown kitchen faucets can leak where the hose connects, so Moen has you confirm the spray wand and pullout hose connection is tight first.

Lift the spout straight off, if your model allows it, and look at the rubber rings on the body. Flat, cracked or gritty rings are finished. Replace them with the exact ones from the maker's kit, using the lubricant the kit calls for.

Call when:

• the water is under the sink and not on top of it, since that is a supply line, stop valve or faucet connection problem rather than a handle problem;
• the handle will not come off, the set screw is stripped, or the cartridge is frozen in place by scale;
• you have replaced the cartridge or O-rings and the faucet still leaks;
• the faucet body or deck has water damage, a soft cabinet floor or mold.

HQ Plumbing and Air is licensed and insured, and we give free estimates and upfront pricing before work starts. If you would rather not take a faucet apart, our residential plumbing team can diagnose the leak and fix it. For a broader look at drips, see how to fix a dripping faucet or the brand page on a leaking Moen bathroom faucet.