Garbage disposal installation: a guide for pros

What customers ask, how to win the job, and what to put on your profile.

Offering garbage disposal installation

Disposal installs are fast when the mount, the drain flange and the outlet match the unit, and slow when they do not. Check all three before you open the box.

What customers ask

  • Will the new disposal fit my sink?
  • Do I need a new switch or outlet?
  • Can you connect the dishwasher to the disposal?
  • Why does the new disposal leak at the mount?
  • Why is the disposal humming and not spinning?

How to win the job

  • On the first call, ask the mount type, the sink flange, the outlet or switch under the sink, and whether the dishwasher drains through the disposal.
  • Bring a mounting kit, a drain flange kit, a dishwasher hose connector, an air gap, a high-loop kit, and a spare cord or switch to the first visit.
  • Turn the power off at the breaker and test it with a meter before you touch any wiring.
  • Show the customer the mount type and the electrical plan before you start, so there are no surprises under the sink.
  • Quote the disposal, the drain parts, the dishwasher connection and the electrical hookup as separate lines.
  • Run water through the disposal and check every joint and the mount for leaks and vibration before you leave.

What to put on your profile

  • Photos of a finished disposal install with the mount, drain and dishwasher connection visible
  • List the disposal brands you install, and note the mount types you handle
  • Note the dishwasher connection work you do, including air gaps and high loops
  • Show a before and after of a stuck disposal replaced, with the switch and wiring visible

Follow-up that helps the customer

  • Offer to check the disposal's mount and drain on the first service call after install
  • Suggest a drain check if the disposal backs up often, since a slow drain line can cause it
  • Recommend a jam-clearing and maintenance walk-through, so the customer knows how to reset the unit

Licenses and permits

Disposal installation's plumbing portion is commonly done by licensed plumbers, and the electrical hookup may need a licensed electrician. Confirm the requirements with your state or local licensing agency before you take the work.

Questions

What do I say when the customer's sink has no switch for the disposal?

Show the options, which are a switch, a cord, or an outlet with a switch. Quote the electrical work to a licensed electrician if your license does not cover it, and say so.

How do I handle a dishwasher drain that has no air gap?

Check the local rule before connecting the line. Where the air gap is required, install it, and quote it as its own line.

How do I handle a disposal that will not spin after install?

Turn the power off and check for a jam with the hex key or the reset button before you blame the unit. A jam is cleared, not a failed install.

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.

Edit history

More plumbing guides for pros

Start here

About this guide

Get garbage disposal installation requests

Customers pick you by name. Signup is free, and you pay only for leads you accept.

Join as a pro
Sign up free