Quick Answer:
If your dishwasher is coughing and you find grit at the inlet, the most common causes are debris trapped in the angle stop or the dishwasher hose screen, loose scale or rust in the branch piping, or material dislodged by a pressure change. Start by shutting off the water, then disconnect the inlet hose and inspect the screen. Clean or replace the screen and flush the line; if the problem returns or you see corrosion, call a professional.
Why This Happens
- Manufacturing or repair work on the street can shake loose mineral deposits and rust in pipes. After that kind of work a homeowner may notice **Black flecks after pressure change** in fixtures.
- Unused sections of plumbing can collect sediment. If part of the line sat idle, you might find **Sediment after long periods of no use** when you reopen it.
- The dishwasher inlet has a small mesh or screen that traps particulates. If the screen is partially clogged, the machine can sound like it’s starving for water while grit accumulates at the inlet.
- Older galvanized or corroding copper pipes can shed particles as they break down. Rubber parts or degraded supply hose liner can also produce flakes or grit.
Step-by-Step What to Do
1. Prepare and shut off water
Locate the dishwasher shutoff (usually an angle stop under the sink) and turn it off. If you’re unsure which valve that is, turn off the main house supply. Place a towel and a small bucket under the connection to catch water.
2. Disconnect the hose and inspect
Disconnect the dishwasher inlet hose at the shutoff or at the dishwasher connection. Disconnect the dishwasher inlet hose and inspect the screen. Look for grit, flakes, or a clogged mesh. If the hose or screen is damaged, plan to replace it.
3. Clean the screen and hose
- Rinse the screen under running water and gently brush with an old toothbrush. Remove trapped particles until water flows freely.
- Flush some water through the disconnected supply line into a bucket to clear loose debris. Reinspect the hose interior for residue.
- If debris is heavy or oily, repeat flushing until the water runs clear.
4. Check nearby fixtures
Run the hot and cold taps at the sink and other nearby fixtures briefly to see if they produce grit. If multiple fixtures show debris, the issue is upstream and not just the dishwasher hose.
5. Reconnect and test
- Reconnect the hose, open the shutoff slowly, and watch for leaks. Run a short dishwasher fill cycle to confirm steady water flow and that no new debris appears at the inlet.
- If the screen clogs again immediately, replace the hose or call a plumber—continued clogging indicates a bigger source of sediment.
What Not to Do
- Do not force dishwasher valves closed when clogged. Forcing can damage the valve seat and make the leak or flow problem worse.
- Do not ignore repeated or heavy debris—this can damage the dishwasher fill valve and pump over time.
- Do not use strong chemical cleaners in the supply line—those are for drains and can damage fittings or seals.
When to Call a Professional
- Debris returns immediately after cleaning or shows up in multiple fixtures—likely an upstream issue.
- You see clear corrosion, rust flakes, or crumbling pipe material at the supply connections.
- The shutoff valve leaks, is stuck, or you cannot isolate the dishwasher without shutting off the entire house.
- Water discoloration persists or the dishwasher shows repeated fill errors after cleaning the screen.
Safety Notes
- Turn the water off before disconnecting the inlet to avoid spraying hot water.
- Unplug the dishwasher or turn off its breaker if you will be working where water could reach electrical parts.
- Wear gloves and eye protection when flushing lines—small particles can become airborne or splash.
- If you’re unfamiliar with plumbing connections, call a plumber to avoid damaging valves and fittings.
Common Homeowner Questions
- Will grit damage my dishwasher? Yes, grit can wear the fill valve and pump seals over time; removing it promptly helps prevent damage.
- Can I clean the screen with vinegar? Yes—soaking a clogged mesh in vinegar can help dissolve mineral deposits; rinse thoroughly afterward.
- Is this a sign my pipes are failing? Not always. It can be temporary (municipal work or disuse), but repeated shedding or visible corrosion should be inspected by a plumber.
For more related articles, see the Black Specks, Sediment, or Grit in Water hub.