A working garbage disposal is one of those things you don't think about until it stops working. Then suddenly every meal cleanup becomes a hassle.

The good news: disposal replacement is one of those repairs that sounds more complicated than it is — at least when you're replacing an existing unit.

Signs Your Disposal Needs Replacing

Humming but Not Spinning

You hit the switch, hear the motor hum, but nothing happens.

Try first:

  1. Turn it OFF
  2. Look for a hex key slot on the bottom
  3. Use an Allen wrench to manually rotate the grinder
  4. Check for jams — something might be stuck

If the motor hums but won't turn even manually, or if it runs but the grinders don't move, the internal components have failed.

Frequent Resets

Every disposal has a reset button (usually red, on the bottom).

Occasional resets: Normal. Usually means it overheated or jammed.

Constant resets: Sign of motor failure or electrical issues.

Leaking

From the top: Usually the sink flange seal. Can sometimes be resealed.

From the bottom: Internal seal failure. Time to replace.

From the side: Dishwasher connection or drain connection. Check and tighten fittings first.

Won't Turn On at All

No hum, no nothing:

  1. Check if the outlet works (plug something else in)
  2. Check the breaker
  3. Try the reset button
  4. If none of that works, the motor is dead

Age

Disposals typically last 8-15 years. If yours is pushing that age and having issues, replacement often makes more sense than repair.

Persistent Odors

If cleaning doesn't help (ice, citrus, baking soda), the grind chamber may have buildup that can't be cleaned. Time for fresh unit.

Understanding Disposal Types

Continuous Feed

Most common type:

  • Flip a switch, disposal runs
  • Add waste while running
  • More convenient for most people

Batch Feed

Safer but less common:

  • Must cover the drain to activate
  • Can't add waste while running
  • Good for families with small children

Motor Size (Horsepower)

  • 1/3 HP: Basic, apartment grade
  • 1/2 HP: Standard for most homes
  • 3/4 HP: Better for heavy use
  • 1 HP+: Heavy duty, less likely to jam

General rule: Get at least 1/2 HP. The price difference is small and the performance difference is significant.

What's Involved in Replacement

The Good News

Replacing an existing disposal is relatively straightforward because:

  • Electrical is already there
  • Plumbing connections exist
  • The sink opening is already cut

Basic Process

  1. Disconnect power — Turn off at breaker
  2. Disconnect plumbing — Discharge tube and dishwasher connection
  3. Remove old unit — Usually a twist-off mount
  4. Install new mounting ring — If not compatible
  5. Connect new disposal — Twist onto mount
  6. Reconnect plumbing — Discharge and dishwasher
  7. Restore power and test

Time Required

For a straightforward swap: 30-60 minutes

Add time for:

  • Corroded or stuck connections
  • Different mounting system than old unit
  • Under-sink obstacles
  • Unexpected plumbing issues

Choosing a Replacement Disposal

Match Your Mounting System

Most disposals use one of a few mounting systems. The easiest replacement uses the same mount as your old unit — you can skip reinstalling the mounting ring entirely.

Common systems:

  • EZ Mount (InSinkErator and clones)
  • 3-Bolt Mount (Waste King and others)

Features to Consider

Sound insulation: Higher-end models are noticeably quieter. Worth it if your kitchen is open to living areas.

Stainless steel grind chamber: Resists corrosion better than galvanized steel.

Auto-reverse: Helps prevent jams by periodically reversing direction.

Cord included: Some units come without a power cord. Check before you buy.

Brand Considerations

InSinkErator: Most common, parts widely available, good quality

Waste King: Good value, often uses different mount than InSinkErator

Moen: Newer to the market, solid options

Store brands: Usually rebranded from major manufacturers

What You Need for Installation

Tools

  • Screwdriver (flathead and Phillips)
  • Pliers or channel locks
  • Plumber's putty
  • Bucket and towels
  • Flashlight
  • Disposal wrench (often included with new unit)

Possibly Needed

  • New mounting hardware (if changing brands)
  • Discharge tube
  • Dishwasher connector
  • Wire nuts
  • Plumber's tape

Common Installation Issues

The Sink Flange Is Corroded

If the mounting flange in the sink is rusted or corroded:

  • Can sometimes be cleaned and reused
  • May need to be replaced
  • Replacement requires removing and reseating with plumber's putty

The Outlet Doesn't Work

Some disposals are hardwired, some plug in:

  • Check if there's an outlet under the sink
  • Verify it's switched (controlled by a wall switch)
  • May need an electrician if hardwired improperly

Plumbing Doesn't Line Up

New disposal may be a different height:

  • May need to adjust discharge tube
  • P-trap might need repositioning
  • Usually solvable with new fittings

No Dishwasher Connection

If you have a dishwasher but the new disposal's knockout isn't removed:

  • Use a screwdriver and hammer to knock it out
  • Remove the knockout disc from inside the disposal
  • Don't skip this — water will back up into the dishwasher

When to Call a Pro

DIY-Friendly

  • Replacing existing disposal with same mount type
  • Basic plumbing reconnection
  • Simple electrical plug-in

Call a Pro For

  • Installing a disposal where none existed (requires plumbing modification)
  • Electrical work (new outlet, hardwiring)
  • Unexpected plumbing complications
  • Septic system considerations

Why We Include This Service

At Finally Fixed Home Services, we replace existing garbage disposals as part of our Home Repair Services. Under Colorado law, replacing an existing disposal using existing plumbing connections doesn't require a plumber's license. We can swap your old unit for a new one, including reconnecting to existing plumbing and electrical.

Note: We can only replace disposals where one already exists. Installing a new disposal where there wasn't one before requires a licensed plumber. See our legal page for details on what we can and can't do.

Maintenance Tips for Your New Disposal

Do

  • Run cold water before, during, and after use
  • Cut large items into smaller pieces
  • Use it regularly (prevents rust and buildup)
  • Clean with ice cubes and citrus periodically
  • Run it until grinding stops completely

Don't

  • Put grease or oil down the disposal
  • Grind fibrous foods (celery, artichokes, corn husks)
  • Grind expandable foods (pasta, rice) in large quantities
  • Grind non-food items (obviously)
  • Use hot water while grinding (melts grease, causes clogs downstream)
  • Put your hand in the disposal (also obviously)

Monthly Cleaning

  1. Dump a tray of ice cubes in
  2. Add a handful of kosher salt
  3. Run the disposal with cold water
  4. Follow with half a lemon or lime

This cleans the grind chamber and freshens odors.

The Bottom Line

If your disposal is humming but not grinding, leaking from the bottom, or just plain dead — replacement is usually the answer. It's a manageable job if you're handy, and a quick job for a pro.

Just make sure you're getting a quality unit (at least 1/2 HP) and match your mounting system for the easiest install.

Need Disposal Replacement?

We replace existing garbage disposals throughout Colorado. Unit selection advice, installation, and testing included.

Check out our full Home Repair Services or see our Minor Repairs service for details.

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