Replacing a bathroom faucet is one of the more approachable plumbing projects in a home. Most of the work happens under the sink, and the parts you need usually come in the box. The steps below cover choosing a faucet that fits, removing the old one, installing the new one and checking for leaks. Always read the instructions that came with your faucet, because mounting hardware varies by brand and model.
Choose a faucet that fits
Match the holes. Count the holes in your sink or countertop and measure the distance between the outer ones. Common layouts are single hole, 4 inch centerset and 8 inch widespread. A single hole faucet can often cover extra holes with a deck plate.
Check the flow rate. California's appliance efficiency rules limit bathroom sink faucets and replacement aerators made on or after July 1, 2016 to 1.2 gallons per minute at 60 psi, so look for a model rated 1.2 or lower. That is stricter than the federal standard of 2.2 gallons per minute and the EPA WaterSense label, which allows up to 1.5. Many WaterSense models run at 1.0 to 1.2 gallons per minute. On a septic system, less water down the drain is a plus.
Look for lead free certification. Federal law limits lead in faucets and other drinking water fixtures to a weighted average of 0.25 percent on the surfaces that touch water. Buy faucets that are certified to that standard, usually marked on the box or in the product listing.
Tools and materials
- New faucet, with its gasket or a small tub of plumber's putty if the instructions call for it
- Adjustable wrench and a basin wrench for nuts behind the sink bowl
- New supply lines if the old ones are kinked, corroded or more than a few years old
- Bucket, towels and a flashlight
- Safety glasses
Step 1: Shut off the water and clear the cabinet
Empty the cabinet and turn both shutoff valves under the sink clockwise until they stop. Open the faucet to release pressure. If the shutoffs do not hold or will not turn, stop here. Forcing an old valve can break it, and it is better to replace it first.
Step 2: Remove the old faucet
Put a bucket under the connections and disconnect the supply lines from the shutoff valves or the faucet. Use the basin wrench to loosen the mounting nuts that hold the faucet to the sink. If you are also replacing the drain, loosen the P-trap slip nuts and remove the drain assembly. Lift the old faucet out and clean old putty, caulk and mineral buildup off the sink.
Step 3: Set the new faucet
Attach the gasket to the faucet base, or apply a thin rope of plumber's putty if the instructions call for it. Feed the supply lines and mounting hardware through the holes, center the faucet, and thread on the mounting nuts from below. Snug them by hand, check the faucet is straight, then tighten with a wrench without overtightening. Wipe away any putty that squeezes out.
Step 4: Connect the supply lines
Connect hot to hot, usually on the left, and cold to cold. Many supply lines seal with a built-in washer, so check the instructions before adding thread tape. Tighten by hand, then about a quarter turn more with a wrench. Overtightening can crack plastic nuts or crush washers.
Step 5: Install the drain, if included
Seat the new drain flange in the sink with the gasket or putty the instructions call for, tighten the nut and gasket from below, connect the pop-up linkage, and reconnect the P-trap to the new tailpiece.
Step 6: Flush and test
Remove the aerator from the spout. Turn the shutoffs on slowly and run hot and cold water for a minute to clear debris, then reinstall the aerator. Check every connection with a dry paper towel, including the faucet base and the drain. Fill the sink, then drain it while watching the trap for drips.
Common problems after installation
| Problem | Likely cause | What to try |
|---|---|---|
| Drip at a supply connection | Nut loose or washer seated crooked | Shut off water, reseat the line, tighten a little more |
| Water at the faucet base | Gasket not seated or mounting nuts loose | Tighten mounting nuts evenly from below |
| Low flow | Debris in the aerator or a valve not open | Clean the aerator and open both shutoffs fully |
| Leak at the drain | Slip nut or drain gasket not seated | Hand tighten slip nuts and check the drain gasket |
| Hot and cold reversed | Supply lines swapped | Shut off water and swap the lines at the shutoffs |
Frequently asked questions
Do I need to replace the shutoff valves too?
Not always. If the valves close fully and do not leak at the stem, they can stay. If they are stuck, corroded or drip when turned, replacing them while the faucet is out is easier than doing it later.
Should I replace the supply lines?
New supply lines are inexpensive and often included with the faucet. Replace lines that are kinked, bulging, corroded or rigid tubing that does not fit the new faucet.
What does a WaterSense label mean on a faucet?
It means the faucet or aerator meets EPA's specification of no more than 1.5 gallons per minute while still providing at least 0.8 gallons per minute at low pressure. In California, also check that the faucet is rated 1.2 gallons per minute or lower to meet the state limit.
How is pricing quoted for faucet installation?
Flat rate pricing, quoted on site before work begins.
Sources
- California Energy Commission, California Code of Regulations, Title 20, Appliance Efficiency Regulations, section 1605.3(h)(2)
- U.S. EPA WaterSense, Bathroom Sink Faucets technical sheet
- U.S. EPA, How does the Safe Drinking Water Act limit lead in pipes, plumbing fittings, fixtures, faucets, solder and flux?
Need help with a faucet installation?
Wade's Plumbing & Septic handles faucet and fixture installation across Santa Cruz County and nearby Santa Clara County communities. Quotes are free and pricing is flat rate, quoted on site before work begins. Request service or call during office hours, Monday to Friday, 9:00 AM to 5:00 PM.
