Sink installation: what to know

What the job involves, what changes the price, and what to ask a pro.

What sink installation is

Sink installation sets a new kitchen or bathroom sink, connects the faucet, supply lines and drain, and seals it to the counter or cabinet so it does not leak. The job depends on the sink type and the counter material, and it is best checked before the old sink is removed.

Signs you need it

  • The current sink is cracked, chipped beyond repair, or stained in a way cleaning cannot fix
  • The sink is the wrong size or hole layout for the counter or the faucet you want
  • The old sink leaks at the rim or the drain, and the cabinet below shows water damage
  • You are remodeling the counter, and the new top needs a different sink type, such as an undermount or farmhouse sink
  • The drain or supply lines are old or in the wrong place for the new sink

What the pro does

  • Check the counter opening and the cabinet, and confirm the new sink fits the cutout and the support brackets
  • Remove the old sink, disconnect the drain and supply lines, and clean the counter surface for the new seal
  • Set the sink with the correct sealant or mounting clips, undermount clips for undermount sinks and a rim seal for drop-in sinks
  • Connect the drain assembly, the trap and the tailpiece with the correct slope and washers
  • Connect the faucet and the supply lines, and check the shutoff valves before you turn the water on
  • Test the drain and the supply under water, and check the seal around the rim for leaks before you leave

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Sink type: undermount, drop-in, farmhouse, vessel and integrated sinks each change the mounting work
  • Counter material, such as stone, solid surface or laminate, and whether the counter must be cut or re-sealed
  • Whether the drain, trap or supply lines must be replaced to fit the new sink
  • Cabinet condition, including any rot or damage at the sink base
  • Whether a faucet, a garbage disposal or a sprayer must be connected at the same time
  • Access under the sink and whether the cabinet or plumbing must be moved

What a written quote should spell out

  • Sink model and type, and how it mounts to the counter
  • Drain assembly, trap and tailpiece, new or reused
  • Supply lines and shutoff valves, new or reused
  • Sealant or clip type and where it is used
  • Who handles any counter cutting or repair, and who is responsible for it

Questions to ask before you hire

  • Does the new sink fit the counter cutout, and will you need to change the cutout?
  • Is the sink undermount or drop-in, and how is it attached?
  • Will you replace the drain assembly and the trap, and what material are they?
  • Who makes the counter cut or repair if the sink does not fit?
  • Will you test the drain and the supply under water before you leave?
  • Does the sink have an overflow, and will the drain connect to it correctly?

Red flags

  • Pro who installs an undermount sink with a silicone bead and no mounting clips
  • Pro who cuts the counter without measuring the fit or confirming the cutout first
  • Pro who reuses a drain assembly that is corroded or cracked
  • Pro who leaves a sink without a water test under the drain

What you can do yourself

A homeowner can set a drop-in sink on a counter that already has a good cutout, if the drain and supply are in good condition. Call a pro for an undermount sink, any counter cutting, any work that moves the drain or supply, or any sink whose cabinet shows water damage, since a bad seal leaks into the cabinet and floor.

Licenses and permits

The plumbing work in a sink install is commonly done by licensed plumbers, and counter cutting may be done by a different licensed trade. Check with your state or local licensing agency about the plumbing portion of your job.

Sink installation questions

Do I need a new drain assembly with a new sink?

In most cases, yes. The old assembly is often corroded or does not fit the new sink's drain hole. A new one is easy to install while the sink is out.

What is the difference between undermount and drop-in sinks?

A drop-in sink sits in the counter opening and is held by a rim, so the rim is visible. An undermount sink is attached below the counter, with a clean edge, and needs solid mounting clips and a good seal.

Why does my new sink leak at the drain?

The most common causes are a missing or misplaced washer, a loose slip nut, or a drain that is not supported. The pro should check each joint and test the drain with water.

Can I install a sink without changing the counter?

Only if the sink fits the existing cutout. A different sink size or type usually means the counter must be cut or replaced.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

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