If the shut-off valves under your sink are inaccessible or seized, you must locate and turn off the main water supply to your entire house before proceeding. Never attempt faucet disassembly with the water supply still on, as this can lead to significant flooding and water damage. Once the main supply is off, open a lower-level faucet to drain the remaining water from the pipes.

While the adjustable wrench and Phillips head screwdriver are essential, it's also helpful to have a small flathead screwdriver or utility knife for prying off decorative caps. A set of O-ring picks can make removing old O-rings easier, and a wire brush can be useful for cleaning mineral deposits on internal components. Having a rag or small bucket ready for drips is also a good idea.

If the leak persists, carefully re-tighten all connections, ensuring they are snug but not overtightened, which can damage parts. Double-check that the new O-rings and washers are correctly sized, seated properly, and that plumber's grease was applied. Sometimes, the faucet seat itself might be worn or corroded, requiring a specific seat wrench for repair or replacement.

The best way to get the correct replacement parts is to take the old O-rings and washers with you to a hardware store to match them for size and material. Alternatively, if you know your faucet's brand and model number, you can often find a repair kit or parts list online. Always apply plumber's grease to new O-rings for a better seal and extended life.