Quick Answer:
If a recently repaired plumbing line now causes the garbage disposal to leak, the most likely cause is a disturbed or loose connection where the plumber worked. Start by turning off power to the unit, then re-check every joint that was touched during the repair and confirm washers are facing the right way. Tightening or reseating the affected fittings usually fixes the leak; if the leak is from the disposal body or the bottom, you may need a replacement or a pro.
Why This Happens
When someone works on the sink, drain, or waste lines, they often remove or loosen fittings that connect to the disposal. Common reasons for a post-repair leak include:
- Slip nuts or hose clamps that were not retightened fully or cross-threaded.
- Washers installed the wrong way or left out entirely.
- Mounting ring or flange misaligned after reinstalling the disposal.
- Cracked or corroded fittings that failed under the disturbance.
- Dislodged dishwasher inlet or drain hose clamp.
Some leaks are obvious spray or streams from a fitting; others drip slowly. If you see water spraying from the disposal area, check the inlet and mounting connections for gaps or misaligned seals—this can look like Water spraying from disposal housing.
Step-by-Step What to Do
1. Cut power and clear the area
- Turn off the disposal at the wall switch and at the circuit breaker to be safe.
- Place a bucket and towels under the sink to catch water.
2. Re-check every joint that was touched
Go through each connection the plumber might have touched and inspect it closely:
- Sink flange and mounting ring — make sure the unit sits square and the mounting lock ring is snug.
- Discharge elbow / trap connection — check slip nuts and washer orientation.
- Dishwasher hose and inlet — confirm hose clamp is tight and the hose is seated.
- Tailpiece and trap — verify slip nuts are hand-tight plus a quarter turn, not over-tightened.
Confirm washers are facing the right way. If a washer has a beveled side, the bevel usually faces the fitting or flange; an upside-down washer can leave a gap and leak.
3. Tighten, reseat, or replace small parts
- Tighten slip nuts and hose clamps evenly; do not overtighten plastic fittings.
- Replace torn or flat washers with the same size and type if needed.
- Reseat hoses and make sure clamps sit over the hose barb.
4. Run a careful test
- Restore power and run water slowly while watching each joint for leaks.
- Run the disposal briefly only if all hands and tools are clear of the unit.
- Have someone observe under the sink while you run water from above.
5. Check the disposal body and bottom
If the fittings are all sound but water still appears, inspect the disposal housing and bottom for cracks or internal leaks. Persistent leaking from the unit’s underside or motor area usually means the unit itself is failing. In that situation, the issue may be Garbage disposal leaking from bottom, which often requires replacement or professional repair.
What Not to Do
- Do not assume the plumber caused it, but do verify every touched fitting and washer orientation.
- Do not run the disposal with your hand inside or with tools still in the chamber.
- Do not use tape or glue as a permanent fix on compression fittings or cracks in the housing.
- Do not overtighten plastic nuts; that can crack the fitting and make the leak worse.
When to Call a Professional
- If the leak continues after you’ve inspected and reseated every joint that was touched.
- If the leak appears to come from the disposal body or motor area.
- If you find cracked fittings that need replacement but you’re not comfortable swapping them out.
- If electrical issues (sparks, tripped breakers) occur when the unit runs.
Safety Notes
- Always switch off the disposal at the breaker before working on connections or removing the unit.
- Use gloves and eye protection when reaching under the sink; sharp edges and dirty water are common.
- Keep tools and hands clear of the disposal chamber when testing or running the unit.
- If you must remove the disposal, support it properly — it’s heavy and awkward.
Common Homeowner Questions
- Why did the leak start right after the repair? — A nearby fitting was likely loosened or a washer was disturbed during the work.
- Can I fix it myself? — Often yes for loose fittings and misplaced washers; stop and call a pro if the body leaks or the repair is beyond your comfort level.
- How do I know if the disposal needs replacing? — If water leaks from the motor area or there are cracks in the housing, replacement is usually required.