Quick Answer:
White grit caught in an aerator is most often mineral scale (calcium or magnesium) or small bits of plumbing material. Remove the aerator and inspect the material to decide the next move. A quick vinegar test and a visual check of other fixtures will tell you whether this is a localized aerator issue or a sign of an upstream problem.
Why This Happens
There are a few common causes:
- Hard water leaves mineral scale that flakes off and catches in screens.
- Recent plumbing work can send tape, plastic shards, or pipe debris downstream.
- Changes in pressure or temperature can cause dissolved minerals or gases to come out of solution and form white particles.
If you recently changed plumbing components such as a pressure-reducing valve or had other work done, that can change flow and pressure and release particles—see Cloudy water after installing PRV for related symptoms to watch for.
Step-by-Step What to Do
Step 1 — Prepare and shut off if needed
Have a towel and a small container ready. For a bathroom or kitchen sink you usually don’t need to shut off the supply, but work slowly to avoid dropping parts down the drain.
Step 2 — Remove the aerator and inspect
Unscrew the aerator from the faucet spout. Note the look of the white material on the screen and in the housing:
- If it’s chalky and crumbly, that’s likely mineral scale.
- If it’s flaky plastic or tape-like, it may be debris from recent work.
- If it’s powdery and dissolves in vinegar, that confirms mineral deposits.
Step 3 — Test a sample
Drop a small amount into plain white vinegar. Minerals will usually dissolve or soften in vinegar; plastic, rubber, and tape will not.
Step 4 — Clean or replace the aerator screen
Soak the screen and housing in vinegar for 15–30 minutes if mineral scale is suspected, then scrub with an old toothbrush. Replace the screen if it’s damaged. Reassemble and run the water to check flow.
Step 5 — Flush and check other fixtures
Run cold and hot water at full flow for a minute to flush loose particles. Check other faucets, showers, and the bathtub to see if the white grit appears elsewhere.
Step 6 — Follow up if particles persist
If cleaning the aerator removes the grit but it returns quickly, collect a sample in a sealed jar and note whether the problem appears in multiple fixtures or only one. That information will help decide if you need a technician or a water test.
What Not to Do
- Do not clean aerators and ignore upstream causes.
- Do not use strong acids or unknown chemicals on plumbing parts.
- Do not assume the material is harmless without checking whether it appears in other fixtures or only at one faucet.
When to Call a Professional
- Particles appear in multiple fixtures after cleaning aerators.
- The material looks like plastic, tape, or pieces of pipe and you can’t find the source.
- Water is discolored, has a strange odor, or you have health concerns.
- You’ve had recent major plumbing work, a new PRV, or a water-treatment device installed and the issue persists.
Safety Notes
- Wear gloves when handling unknown materials.
- Do not taste or deliberately ingest water samples.
- Avoid harsh cleaners that can damage faucet finishes or seals.
- If you suspect contamination, stop using the water for drinking and contact your water utility or a certified plumber.
Common Homeowner Questions
- Is it dangerous? Usually not—most white grit is mineral scale, which is not toxic, but check other fixtures to be sure.
- Will vinegar remove it? Yes, vinegar often dissolves mineral deposits on aerator screens; soak and scrub gently.
- Why does my cold water look cloudy? Air, fine mineral particles, or recent changes in plumbing can make water look cloudy—compare symptoms to Milky-looking water from cold tap and check aerators and recent work.
For more related articles, see the White Particles, Cloudy Water, or “Milky” Water hub.