Quick Answer:
If water appears only while the dishwasher drains, the most likely cause is a loose or damaged drain hose connection where it meets the garbage disposal or sink drain. Start by watching one full drain cycle and inspect the hose clamp and connection for visible drips. Many leaks are fixed by tightening or replacing the clamp or hose; if the hose or disposal flange is damaged, call a plumber.
Why This Happens
When a dishwasher drains it forces a concentrated flow of water and occasional food particles through the drain hose. If the hose, clamp, or the fitting on the disposal/sink is loose, cracked, or blocked, pressure during the drain cycle can push water out at the connection. Other causes include a clogged disposal outlet, a missing or damaged knockout plug in a newly installed disposal, or a hose with age-related cracks.
If the issue started after recent plumbing work or seasonal maintenance, check guides like Disposal leaks after plumbing repair and Disposal leaks after winterization for related causes and tips.
Step-by-Step What to Do
1. Prepare and watch a drain cycle
- Clear under-sink items so you can see and work safely.
- Place towels and a shallow pan under the connection to catch drips.
- Run a normal drain cycle and watch closely. Watch the dishwasher drain cycle and inspect the hose clamp and connection for drips.
2. Identify where the water comes from
- Is the water coming from the hose clamp, the hose itself, the disposal flange, or a seam on the disposal? Note exact location and timing (during pump start, midway, or at end).
3. Tighten or replace the hose clamp
- Turn off dishwasher power (or unplug) and keep towels in place.
- If the clamp is a worm-gear screw clamp, use a screwdriver to tighten it snugly—not so tight you damage the hose.
- If the clamp is old, corroded, or the hose slips, replace it with a new stainless steel clamp sized for the hose.
4. Inspect the hose and fitting
- Look for splits, bulges, or soft spots in the hose. Replace the hose if damaged.
- Check the disposal inlet for a missing knockout plug (if disposal was recently installed) or a damaged coupling.
- If the hose attaches to a plastic elbow or connector that’s cracked, replace that part.
5. Test carefully
- Put everything back so it’s dry, then run a short drain cycle while watching. Have towels ready and a helper if useful.
- If tightened clamp solved it, run a full cycle to confirm no slow leaks appear later.
What Not to Do
- Do not run the dishwasher if the connection is actively leaking—cabinet damage can happen fast.
- Do not overtighten clamps to the point of cutting the hose or stripping threads.
- Do not use clear tape or glue as a permanent repair on a pressurized drain hose connection.
When to Call a Professional
Call a plumber if:
- The hose and clamp are in good condition but the leak continues.
- Water appears under the disposal, from the disposal seam, or from hard‑to‑access fittings.
- There is active water damage, mold, or the leak appears to be from inside the dishwasher rather than the drain hose.
If a recent installation or repair preceded the leak, or if you suspect the disposal connection is faulty, a pro can diagnose and fix hidden issues safely.
Safety Notes
- Turn off power to the dishwasher before working under the sink—unplug it or switch the breaker off.
- Wear gloves and eye protection when handling hoses and disposal parts; food particles and sharp edges can cause injury.
- Avoid using bleach or strong chemicals to clear clogs while you have exposed connections; rinse thoroughly if chemicals were used previously.
- Work with towels and a pan to catch water; do not leave standing water in cabinets where electrical components are present.
Common Homeowner Questions
- Q: How long will a tightened clamp last?
A: Often for years if the hose is healthy and not under stress; replace the clamp if corroded. - Q: Can I use plumber’s tape on the hose connection?
A: No—plumber’s tape is for threaded fittings; replace the clamp or hose for a reliable seal. - Q: Could the dishwasher itself be leaking into the drain hose?
A: Yes—internal leaks (pump seal, door gasket) can send water into the hose; a pro can confirm.