How to Descale a Faucet

The seat is the surface on which the valve seal rests to prevent water from flowing when the valve handles are turned. This internal part of the faucet may be worn or scaled, causing repeated leaks. Here, the seat should be lapped. Honing flattens the center of the valve heads, allowing the valve to seal when the valve is closed.

Begin by removing the valve handles

Switch off both the hot and cold water supplies to the faucet. To access the faucet head seats, remove the faucet handles. Using pliers, unscrew the faucet handle cover. The cover comprises the red or blue colored pad (water temperature) on some faucet types, which you may remove with a short flat screwdriver. Then, unscrew the fixing screw located inside the head. Remove the faucet head by pulling it out along its tilt axis.

Note: on some faucet models, the head is just inserted. To remove the head, pull it out along its tilt axis.

Remove the valve heads

With the wrench, unscrew the faucet head’s nut. If you cannot loosen the nut, apply a degreasing agent to it and leave it on for a few minutes. Finish unscrewing the valve head by hand.

Note: Sometimes, it is normal for a trickle of water to come out of the faucet after removing the head.

Grind the seats of the faucet heads

A honing tool comprises a handle, a threaded sleeve with one or more threads, and a collection of varied-sized burrs. The bur is the element that will grind the inside of the faucet to smooth it and descale it.

Using the honing tool, check the condition of the seat, first visually and then with your finger, to feel for any roughness or deformation. Equip the lapping device with a burr of the same diameter as the valve seal. Select the same size screw pitch as the head, then screw the rod into the handle location. Do not force! As you push, turn the knob on the rod two or three turns, then recheck the seat. Remove any debris with an old toothbrush and cloth.

Using the honing tool, check the condition of the seat, first visually and then with your finger, to feel for any roughness or deformation. Equip the lapping device with a burr of the same diameter as the valve seal. Select the same size screw pitch as the head, then screw the rod into the handle location. Do not force! As you push, turn the knob on the rod two or three turns, then recheck the seat. Remove any debris with an old toothbrush and cloth.

Replace the faucet heads

You can then insert the faucet heads into their slots and screw on the nuts on the faucet heads.

Replace the faucet handles

Place the body of the faucet handles on their location. Tighten the fixing screw located inside the faucet head. Screw on the cover or replace the blue (right handle) or red (left handle) colored pad.

Check the faucet

Run the water and check that the faucet no longer splashes and that the water flow has returned to normal.

The lapping of the valve head seats is a repeatable process. However, worn faucet head seats are a sign that your faucet will soon need to be replaced.

Installing a filter or water softener will prevent scale build-up and extend the life of your faucet.

Equipment for descaling faucet head seats

Read more:

How to Descale a Water Heater