Quick Answer:
Brown water at only the upstairs fixtures usually means the problem is confined to the upstairs branch or the hot-water system serving the upper floor. Run quick tests of cold-only and hot-only at an upstairs tap, then compare those same tests at a downstairs tap to see whether the discoloration follows the hot line, the cold line, or only the upstairs riser.
Why This Happens
- Corroded or aged vertical risers carrying cold water to the upper floor can shed rust and sediment into those fixtures.
- If only hot taps upstairs are brown, the water heater or its upstairs distribution pipe may have rust or sediment.
- Local work or a pressure surge can loosen deposits and cause temporary discoloration—see Discoloration after pressure surge and Rust-colored water after city work for related situations.
- Clogged aerators or short sections of corroded branch piping can also cause the problem to appear only at certain fixtures.
Step-by-Step What to Do
Step 1 — Confirm it’s only upstairs
Choose one upstairs fixture and one downstairs fixture for comparison. Use a clear glass so you can judge color easily.
Step 2 — Test upstairs cold-only
- Turn off the hot handle and fully open the cold. Let it run for 30–60 seconds and observe clarity in the glass.
- Note whether the cold stream is brown, rusty, or clears after a minute. If cold upstairs is brown but downstairs cold is clear, the upstairs cold riser or branch is likely the source.
Step 3 — Test upstairs hot-only
- Turn off the cold handle and run only hot at the same upstairs fixture. Observe the color.
- If hot upstairs is brown but cold upstairs is clear, suspect the water heater or the hot distribution to the upper floor.
Step 4 — Compare downstairs cold and hot
- Repeat cold-only and hot-only tests at a downstairs fixture. If downstairs is clear for both, the issue is isolated to upstairs piping or water heater branches.
Step 5 — Check simple fixture items
- Remove the aerator screen from the affected faucet and inspect for rust or debris. Clean and retest.
- Check the shutoff valves under the sink—if a valve is corroded inside it can introduce rust when moved.
Step 6 — Consider the hot-water supply
- If the problem appears only when hot water runs at multiple upstairs fixtures, the heater or its upstairs hot run may need attention. If the heater serves multiple floors, compare upstairs and downstairs hot tests to narrow it down.
Step 7 — Document and monitor
- Note when the issue started, any recent work, and whether running the water clears the color. Take clear notes or photos to share with a service professional if needed.
What Not to Do
- Do not open walls until you prove it is isolated to upper risers.
- Do not use chemically aggressive cleaners in plumbing to try to clear rusted pipes; that can cause damage or unsafe reactions.
- Do not assume the problem is harmless—persistent brown water can stain laundry or indicate failing pipe material that needs repair.
When to Call a Professional
- Call a plumber if brown water persists after basic tests, if multiple upstairs fixtures are affected, or if you smell rotten eggs or see black solids—these can indicate a failing water heater or serious pipe corrosion.
- Call immediately if the water is heavily discolored and you suspect compromised water quality for drinking, cooking, or bathing.
- If you find corrosion under a sink, a professional can inspect the riser, valves, and connections safely and advise on repair or replacement.
Safety Notes
- Avoid drinking or cooking with visibly discolored water until the source is identified and cleared.
- If you need safe water for drinking or cooking, use bottled or otherwise known-safe water until the issue is resolved.
- Turn off appliance use (washing machine, dishwasher) if they would draw discolored water that could stain fabrics.
Common Homeowner Questions
- Q: Will running the tap clear the brown water?
A: Sometimes short runs clear loose sediment, but persistent discoloration needs diagnosis. - Q: Could this be the municipal supply?
A: If only upstairs is affected, it’s usually internal plumbing; if whole house shows brown, contact the water utility. - Q: Is the water safe to bathe in?
A: Brief contact is usually not hazardous, but avoid using discolored water for drinking or open wounds until fixed.
For more related articles, see the Brown or Rust-Colored Water Events hub.