What you need to do before you start
Replacing a kitchen faucet with a sprayer is a job you can do yourself in about an hour if you have the right tools and follow the steps in order. The work happens under the sink, so start by turning off the water supply — look for two valves (one for hot, one for cold) under the basin and turn both clockwise until they stop. If you cannot find shut-off valves under your sink, locate the main water shut-off for your house, usually in the basement or near the water meter.
Before you buy a new faucet, measure the distance between the holes in your sink or countertop where the old faucet is mounted. Most kitchen sinks have either a single hole (for a single-handle faucet) or three holes (for a two-handle faucet with a sprayer). A faucet with a sprayer typically needs either one hole (if the sprayer is built into the faucet body) or two holes (if the sprayer is a separate piece). Knowing your hole count and spacing prevents buying a faucet that will not fit your sink.
Key Takeaways
- Turn off the water supply under the sink before you disconnect anything, and turn on the faucet to release pressure in the lines.
- Disconnect the hot and cold supply lines by hand or with an adjustable wrench, then remove the mounting nuts holding the old faucet in place from underneath.
- Install the new faucet by inserting it through the holes, tightening the mounting nuts from below, and reconnecting the supply lines to the correct ports.
- Test for leaks at the connection points before you turn the water back on fully, and adjust the sprayer hose if it kinks or does not reach the sink properly.
Removing the old faucet
After the water is off, turn on the faucet at the sink to release any pressure still in the lines. Place a bucket or towel under the supply lines to catch any water that drips when you disconnect them. Most supply lines are connected with compression fittings — nuts that screw onto the faucet ports. Use an adjustable wrench to hold the fitting nut while you turn the compression nut counterclockwise with a second wrench. Work slowly so you do not strip the nut.
Once the supply lines are free, look underneath the sink for the mounting nuts that hold the faucet to the sink or countertop. These are usually large nuts on threaded bolts that come up through the holes. Use an adjustable wrench or basin wrench (a specialized tool that fits in tight spaces) to turn these nuts counterclockwise. A basin wrench is worth renting from a hardware store if the space is tight — it saves time and frustration. Once the nuts are loose, lift the old faucet out from above the sink.
If the old faucet has a sprayer hose, disconnect it by unscrewing the hose from the faucet body or from a separate spray valve under the sink. Some hoses are held in place with a clip — pry the clip gently with a flathead screwdriver to release it. Clean away any mineral buildup or debris from the sink holes before you install the new faucet.
Installing the new faucet and sprayer
Read the instructions that come with your new faucet before you start. Different brands have different mounting systems, and the instructions will show you the exact order of washers, nuts, and adapters. Most faucets come with a rubber gasket or mounting ring that sits on top of the sink to seal the gap between the faucet base and the sink surface.
Insert the faucet through the holes from above, making sure the gasket or mounting ring is in place. From underneath, hand-tighten the mounting nuts onto the threaded bolts. Once they are snug, use a wrench to tighten them another quarter turn — do not over-tighten, as this can crack the sink or strip the threads. The faucet should be stable but not forced.
Connect the hot and cold supply lines to the correct ports on the new faucet. The hot line (usually marked red or with an H) goes to the hot port, and the cold line (usually marked blue or with a C) goes to the cold port. Hand-tighten the compression nuts first, then use a wrench to snug them — again, quarter turn past hand-tight is enough. If your new faucet has a separate sprayer, screw the hose onto the spray valve under the sink and find it with the clip provided.
Testing and adjusting
Before you turn the water back on at the main shut-off, turn the shut-off valves under the sink counterclockwise slowly — this lets water back into the lines gradually and prevents air locks. Open the faucet handle and let water run for 10 to 15 seconds to flush out any debris from the lines. Check all the connection points — the supply line nuts, the mounting nuts, and the sprayer hose connection — for drips.
If you see a drip at a compression fitting, try tightening the nut a quarter turn with a wrench. If it still drips, turn the water off, disconnect the fitting, and check that the ferrule (the small metal ring inside the nut) is seated properly. Sometimes the ferrule shifts during installation and needs to be repositioned. Reconnect and test again.
Test the sprayer by pulling it out and running water through it over the sink. If the hose kinks or does not reach where you need it, adjust the hose routing under the sink or replace it with a longer one (most hardware stores sell replacement hoses in different lengths). Make sure the hose does not touch hot pipes or sharp edges, as this can damage it over time.
Common problems and fixes
If water leaks from under the sink after installation, the most common cause is a loose compression fitting. Turn off the water, tighten the nut a quarter turn, and test again. If tightening does not stop the leak, the ferrule may be damaged and need replacement — this requires disconnecting the line and buying a new ferrule kit from a hardware store.
If the sprayer does not spray but water comes out of the faucet normally, the sprayer hose may be kinked or the diverter valve (the part inside the faucet that directs water to the sprayer) may be stuck. Try straightening the hose first. If that does not work, turn off the water and disconnect the sprayer hose from the faucet. Run water into a bucket to flush the line — sometimes mineral deposits block the opening. Reconnect and test.
If the faucet handle is hard to turn or does not move smoothly, you may have over-tightened the mounting nuts, which can bend the faucet body slightly. Loosen the mounting nuts a quarter turn and test the handle. If it moves freely, leave it there. If it is still stiff, loosen another quarter turn.
Tools and materials you will need
Gather these items before you start: an adjustable wrench (or two, so you can hold one fitting while turning another), a basin wrench if the space under your sink is tight, a bucket or towel to catch water, a flathead screwdriver, and the new faucet with sprayer. Most new faucets come with mounting hardware, supply line adapters, and a sprayer hose, but check the box before you buy to make sure. If you are replacing supply lines as well (old ones are often corroded or kinked), buy new braided stainless steel lines — they last longer than rubber and are easier to work with.
A headlamp or small flashlight is useful for seeing under the sink, and a small bowl or cup helps you catch drips as you work. If you do not own a basin wrench and the space is very tight, renting one costs a few dollars and saves your hands from cramping.
Frequently Asked Questions
Do I need to turn off water at the main if I have shut-off valves under the sink?
No. The valves under the sink control water to that faucet only. Use those first — they are faster and easier. Only go to the main shut-off if the under-sink valves are missing, broken, or do not stop the water flow completely.
What if the old faucet is stuck and will not come out?
Spray the mounting nuts with penetrating oil (like WD-40) and let it soak for 15 minutes. Try loosening the nuts again. If they still will not budge, you may need to cut the supply lines with a hacksaw to remove the old faucet, then install new lines with the new one. This adds time but is not difficult.
Can I install a single-hole faucet with sprayer in a three-hole sink?
Yes. You will need a deck plate or escutcheon (a trim ring that covers the unused holes). Most single-hole faucets with sprayers come with one, or you can buy one separately at a hardware store. The plate sits on top of the sink and hides the extra holes.
How tight should the mounting nuts be?
Hand-tight plus a quarter turn with a wrench. The faucet should not move or rock, but you should not need to strain to tighten it. Over-tightening can crack the sink or bend the faucet body, making the handle hard to turn.
What if water comes out of the sprayer even when I am not pulling it?
The diverter valve inside the faucet is stuck open. Turn off the water and disconnect the sprayer hose from the faucet. Run water into a bucket to flush the line and clear any mineral deposits. If that does not work, the diverter may need replacement — contact the faucet manufacturer for a replacement part or consider replacing the faucet.