Step 6 · Inspect and Replace O-Rings and Seals

Examine the O-rings and rubber seals on the old cartridge and within the faucet body. If they appear cracked, brittle, or flattened, replace them. It's often best to replace the entire cartridge if O-rings are worn, as this is a common source of leaks. You can also clean any mineral deposits from the cartridge seat in the faucet body.