How to Install a 3-Hole Bathroom Faucet? | Step-By-Step

A 3-hole bathroom faucet mounts through the sink’s three holes, secures from underneath, and connects to the hot and cold supply lines.

For the full breakdown, see our best 3 Hole Bathroom Faucet guide.

A bathroom faucet swap usually fails at one of two moments: a mounting nut that never got snug, or a supply connection overtightened until the threads gave. Learning how to install a 3-hole bathroom faucet the right way prevents both, and most DIYers finish in about an hour.

Before you buy anything, count the holes in your sink and measure from the center of the left hole to the center of the right hole. Centerset faucets match the common 4-inch 3-hole spacing, while widespread models need roughly 8 inches between the outer holes, so that measurement decides which faucet fits. If you’re still choosing between models, the best 3-hole bathroom faucets we’ve tested cover both layouts.

Installing a 3-Hole Bathroom Faucet: The Step Order That Works

A 3-hole faucet install comes down to one order: shut off the water, pull the old faucet, set the new one from above, secure it from below, then test for leaks. Home Depot’s bathroom faucet installation guide follows that same sequence.

1. Shut off the water. Turn both shutoff valves beneath the sink clockwise until they stop. If there are no local valves, shut off the home’s main supply instead. Keep a bucket and rags under the work area, and unplug the garbage disposal first if one is installed.
2. Drain the lines. Open the faucet handles and let the remaining water run out. That relieves pressure before you break any connection loose.
3. Remove the old faucet. Unscrew the supply hoses from the shutoff valves, loosen the mounting nuts underneath with a basin wrench, and lift the old faucet out from above.
4. Clean the sink surface. Scrape off old putty, caulk, or mineral buildup around the three holes so the new gaskets seat flat.
5. Set the gaskets and faucet. Place a rubber gasket or trim ring over each hole, feed the new faucet’s supply lines down through the holes, and press the body and handles flat against the sink.
6. Secure the hardware from below. Slide a rubber washer, then a brass washer, then the threaded locknut onto each stud. Tighten by hand first, snug the set screws, and finish with a basin wrench — firm, not forced.
7. Connect the supply lines. Attach the hot and cold hoses to their matching shutoff valves and tighten until snug. Apply plumber’s tape only where the instructions call for it.
8. Test for leaks. Turn the water back on slowly, open both handles, and check every connection you touched. If a joint drips, tighten it gently, wipe it dry, and recheck.

You’ll know the install worked when both handles run smoothly and every nut and hose underneath stays dry. One caution every guide repeats: supply fittings get tightened until snug, not as tight as they’ll go — overtightening is the mistake that cracks nuts and crushes washers.

Can a One-Hole Faucet Fit a Three-Hole Sink?

Yes, with a deck plate. A deck plate, sometimes called a trim plate, bridges the two unused outer holes so a single-hole faucet can mount in the center opening of a three-hole sink.

The plate sits flat against the sink and hides the extra holes underneath, giving the installation a finished look. Not every faucet includes one, so check the parts list before you assume it’s in the box — if it’s missing, you can buy a plate separately and match it to the faucet’s finish.

Which Side Gets the Hot Handle?

Put the hot handle on the left and the cold handle on the right, which is the standard U.S. layout for a two-handle bathroom faucet. Most centerset 3-hole models ship as one piece with the handles already connected, so the side is fixed from the factory.

For two-handle faucets that assemble separately, look for the small H and C stamps on the valve bodies before you lock anything down. Then confirm each supply hose runs to the matching shutoff valve so you don’t cross the lines.