Quick Answer:

If brown water appears at a bathroom sink right after renovation or plumbing work, it’s usually loose rust, solder or pipe debris that was disturbed during the work. Start by flushing the lines, clean the aerator, and check for pipe debris before using the water for drinking. If the problem persists or you see flakes of rust, call a professional.

Why This Happens

Renovation can knock sediment and corrosion loose inside pipes, especially in older homes or when supply valves are turned off and back on. That disturbed material flows to the fixtures and can make water look brown or leave particles in the flow. Hot water heaters can also release rusty water when they are disturbed.

If water sits in a disturbed line it can appear cloudy or murky later — read more about Bathroom Sink Water Is Cloudy After Sitting for a related situation. Small particles and solder flux from recent work are common causes; typically the discoloration clears with proper flushing.

Step-by-Step What to Do

1. Stop and assess

• Don’t use discolored water for drinking, cooking, or brushing teeth until it clears.
• Check other fixtures (kitchen, other bathrooms) to see if the issue is isolated to one sink or affects the whole house.

2. Flush lines

• Open the cold and hot taps at the affected sink and run them at full flow for at least 5–10 minutes. If brown water is heavy, run longer (15–20 minutes) until it clears or becomes noticeably lighter.
• Open an outdoor hose bib or another faucet at the same time if you have one; flushing multiple outlets can speed removal of debris from the service line.

3. Clean the aerator

• Unscrew the faucet aerator and check for particles or brown staining. Rinse the screen under clean water and remove trapped debris.
• Soak a metal screen briefly in white vinegar if mineral deposits are stubborn, rinse well, and reinstall.

4. Check pipe debris

• Inspect the sink drain and the P-trap for visible debris. Place a small bucket under the trap, loosen the slip nuts, and remove it to look for sediment or flakes. Clean and reinstall carefully.
• If you find a lot of rust or chunks of material inside the trap or visible in the supply lines, stop and consider a professional inspection — excessive debris can indicate corroding pipes.

5. Test and monitor

• After flushing and cleaning, run the faucet again and check water clarity. Watch for particles or a return of brown color.
• If the flow sputters or pulses after reopening valves or shutoffs, consider checking valve seating or see guidance on Bathroom Sink Sputters After Water Shutoff.

What Not to Do

• Do not ignore rust flakes — they indicate corrosion that can worsen.
• Do not drink, cook with, or bathe in visibly discolored water until it clears.
• Do not pour strong drain chemicals down the sink to “clear” brown water; they won’t fix pipe sediment and can be hazardous if mixed with other substances.
• Do not force or hammer fittings; improper force can cause leaks or damage to new work.

When to Call a Professional

• Brown water persists after thorough flushing and aerator cleaning.
• Multiple fixtures throughout the house show discoloration or sediment.
• You find significant rust or chunks inside traps or pipes, or notice leaks when inspecting fittings.
• There is a strong metallic or chemical smell, or anyone in the home becomes ill after using the water.

Safety Notes

• Wear gloves and eye protection when removing a P-trap or cleaning an aerator.
• Collect water in a bucket when opening traps to avoid spills on floors or cabinets.
• If you’re unsure how to shut off the water safely or remove fittings, stop and call a plumber to avoid causing leaks or water damage.

Common Homeowner Questions

• Why did only one sink turn brown? Often the latest work disturbed sediment local to that branch of piping or the fixture’s aerator and trap trapped debris.
• How long should I flush the lines? Start with 5–10 minutes; if heavy discoloration continues, flush up to 15–20 minutes or until the water clears.
• Is brown water dangerous? Short-term exposure is usually not toxic but it’s best not to ingest it; brown water can contain rust or other particles and should be cleared before drinking.