Q: How do I replace a cartridge on a single-handle faucet?

Ceramic Cartridge

1. Ensure the water supply to the faucet is turned off.
2. Remove the handle (see FAQ 34).
3. Remove the decorative cap by hand-loosening, rotating counter-clockwise.
4. Remove the bonnet nut using an adjustable wrench, rotating counter-clockwise.
5. Remove and replace the cartridge ensuring the pins are aligned with the holes in the valve body.
6. Reinstall the bonnet nut and hand-tighten. When snug, tighten an extra half-turn.
7. Check for leaks by turning on the faucet. If leaking, tighten the bonnet nut until the leaking stops.
8. Reinstall the decorative cap.
9. Reinstall the handle.

Washerless Cartridge

1. Ensure the water supply to the faucet is turned off.
2. Remove the handle (see FAQ 34).
3. Remove the bonnet nut using pliers with protected jaws, rotating counter-clockwise.
4. Lift the ball and packing out.
5. Remove the seat washers and springs.
6. Replace with new seat washers and springs ensuring the cone-shaped spring has the small end facing up.
7. Reinstall the ball and the packing ensuring the tabs are aligned with the slots in the valve body.
8. Reinstall the bonnet nut.
9. Reinstall the handle.