Did you shut off both hot and cold angle stops under the sink, then open the old faucet to confirm flow stops completely?

If the angle stops are old and corroded, cycling them sometimes makes them leak. Test before committing.

Get under the sink with a flashlight. How tight is the access to the faucet mounting nuts?

On most kitchen sinks the mounting nuts are buried behind the sink basin. A basin wrench is almost always required.

Is the disposal (or other under-sink equipment) safe to disconnect at the outlet and slide out of the way, and then plug back in when you're done?

Unplug the disposal at the outlet before doing anything underneath it. If it's hard-wired, leave it alone unless you're comfortable with electrical.

What do the existing supply line connections look like at the angle stops and at the faucet shanks?

Count the holes in your sink deck (or countertop) and compare to the new faucet's hole requirement.

Common combos: 1-hole single-handle, 3-hole 4" centerset, 3-hole 8" widespread, 4-hole with separate sprayer/soap dispenser. A deck plate (escutcheon) can cover extra holes; nothing can add holes.

Do you have: basin wrench, adjustable wrench or channel locks, bucket and towels, flashlight or headlamp, new braided stainless supply lines (if not included), and PTFE tape?

plumbing troubleshooting

Replace kitchen faucet

Common symptoms: replace kitchen faucet; install kitchen faucet; new kitchen faucet; sprayer replacement; faucet swap

Stop and call a pro if:

tight cabinet space — basin wrench likely required
potential disposal disconnect
old corroded shutoffs may fail when cycled

Step-by-step diagnostic flow

Step 1
Did you shut off both hot and cold angle stops under the sink, then open the old faucet to confirm flow stops completely?
If the angle stops are old and corroded, cycling them sometimes makes them leak. Test before committing.
Step 2
Get under the sink with a flashlight. How tight is the access to the faucet mounting nuts?
On most kitchen sinks the mounting nuts are buried behind the sink basin. A basin wrench is almost always required.
Step 3
Is the disposal (or other under-sink equipment) safe to disconnect at the outlet and slide out of the way, and then plug back in when you're done?
Unplug the disposal at the outlet before doing anything underneath it. If it's hard-wired, leave it alone unless you're comfortable with electrical.
Step 4
What do the existing supply line connections look like at the angle stops and at the faucet shanks?
Step 5
Count the holes in your sink deck (or countertop) and compare to the new faucet's hole requirement.
Common combos: 1-hole single-handle, 3-hole 4" centerset, 3-hole 8" widespread, 4-hole with separate sprayer/soap dispenser. A deck plate (escutcheon) can cover extra holes; nothing can add holes.
Step 6
Do you have: basin wrench, adjustable wrench or channel locks, bucket and towels, flashlight or headlamp, new braided stainless supply lines (if not included), and PTFE tape?

Possible outcomes

You're ready — proceed with the swap

high confidence

Water is controlled, access is workable, connections are sound, and the faucet matches your sink.

Safe next steps

Lay a towel and a small bucket under the angle stops to catch residual water
Disconnect the old supply lines at the angle stops first, then at the faucet shanks
Use the basin wrench to back off the faucet mounting nuts; lift the old faucet out from the top
Clean the deck, drop in the new faucet (with deck plate / gasket per the maker's instructions), tighten mounting hardware from below
Connect new braided stainless supplies — hand-tight plus a quarter turn with a wrench, not gorilla-tight
Open the angle stops slowly, run hot and cold, check every joint for drips, then pull the aerator and flush debris for 30 seconds

Stop — fix the angle stops first

high confidence

If a shutoff won't fully close, you can't safely disconnect the supply at the faucet.

Safe next steps

Run the angle-stop-replacement workflow
Or shut off the house main and replace both angle stops now, then restart this workflow

One or both angle stops won't shut off completely

Pause — get help moving the disposal

medium confidence

You shouldn't fight a disposal you're not sure how to disconnect — and you shouldn't work around it either, because you can't reach the mounting nuts.

Safe next steps

If hard-wired, have an electrician or pro disconnect at the disposal whip
If it's a stuck mounting ring, look up the disposal model's removal instructions and try again with the right tool

Stop — call a pro for seized supply nuts

medium confidence

Seized nuts often require heat or cutting, which risks damaging the angle stop or the supply behind the wall.

Safe next steps

Photograph the angle stops and supply nuts
Leave them in place for a plumber to assess

What to document for a pro

Photo of angle stops and supply lines
Pipe material in the cabinet (copper, PEX, galvanized)

Supply nuts seized and require heat or cutting

Pause — buy a deck plate first

high confidence

An exposed extra hole is ugly and leaks crumbs and water into the cabinet. Match a deck plate to your faucet before you start.

Safe next steps

Check the faucet maker's accessories list for a matching escutcheon
Or buy a hole-cover that matches the faucet's finish

Stop — wrong faucet for this sink

high confidence

You can't add holes to a stainless or composite sink without specialty tooling. Pick a faucet that fits the existing hole count.

Safe next steps

Return / exchange the new faucet for a model that matches your hole count
If you're set on the new faucet, get a quote from a fabricator to add a hole — usually not worth it

Sink has fewer holes than the new faucet needs

Pause — gather tools before starting

high confidence

Halfway through a faucet swap is the wrong time to discover you don't have a basin wrench.

Safe next steps

Buy: basin wrench, PTFE tape, new braided stainless supply lines (3/8" comp × 1/2" FIP is typical)
Stage a bucket, towels, and a headlamp under the sink

Diagnostic guidance only. If unsure, stop and call a licensed professional — gas, electrical, and refrigerant work is hazardous to untrained users.

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