Quick Answer:
A loud pressure event followed by brown water usually means sediment or rust was scoured from the service line or main. Attach a pressure gauge to an outdoor hose bib and log any pressure spikes before the discoloration appears, flush cold taps until the water clears, and document what you see. If the problem repeats or you record unusual pressure behavior, contact your water utility or a licensed plumber.
Why This Happens
Water mains and older service pipes collect mineral deposits and rust. A sudden pressure surge — from a nearby main break, a large hydrant use, or a valve operation — can loosen that material and send it into your house plumbing. The brown color is usually iron or other harmless sediments, not bacteria, but it can stain laundry and fixtures.
It can look like Brown water during seasonal changes, which also causes discoloration, but the key difference here is the clear pressure event that preceded the brown water.
Step-by-Step What to Do
1. Check immediate safety and isolate uses
- Stop using hot water to avoid staining clothes and linens.
- Do not run dishwashers or washing machines until the water is clear.
2. Attach a pressure gauge and start logging
- Attach a simple pressure gauge to an outdoor hose bib (hose connection). If you have an electronic gauge with logging, use that; a manual gauge is acceptable.
- Record baseline pressure, then log readings at regular intervals (for example, every 5–15 minutes) and note the time you first see discoloration.
- Attach before trouble appears if possible, so you capture the spike. In practice: attach now and monitor for 24–48 hours to capture intermittent events.
- Attach a pressure gauge to a hose bib and log spikes before discoloration appears — this data helps determine whether the issue is a one-time surge or an ongoing pressure problem.
3. Flush cold-water taps
- Open a cold-water tap at the lowest point in the house (basement or outdoor hose) and one at the highest point, and let cold water run for 10–20 minutes or until it clears.
- Run one tap at a time to avoid sending more sediment through appliances.
4. Document what you observe
- Note which fixtures produced brown water (cold, hot, or both), the timing, and whether pressure dips or spikes accompanied the event.
- Keep photos or short video of discolored water for your records and to share with the utility or plumber.
5. Review the logged pressure data
- Look for sudden spikes or drops that line up with discoloration times. Repeated spikes indicate a system problem rather than a single loose deposit.
What Not to Do
- Do not adjust the PRV until surge data is collected. Changes to the pressure-reducing valve can mask the root cause and make diagnosis harder.
- Do not keep using hot water or run laundry appliances until the water runs clear to avoid staining fabrics.
- Do not assume the problem is only cosmetic if you notice a strong odor or persistent discoloration — document and report it.
When to Call a Professional
- Call the water utility if many homes on your street are affected or if you see main breaks, persistent pressure loss, or ongoing discoloration.
- Call a licensed plumber if your pressure logs show repeated large spikes or if only your property is affected. A plumber can inspect the service line, PRV, and internal piping.
- Call a professional immediately if the water has a sewage smell, if you see particles that look like sand or black debris, or if you have health concerns.
Safety Notes
- Brown water is often iron and not an immediate health risk, but avoid drinking it until it clears. Use bottled water if in doubt.
- Do not use hot water for bathing or cooking while discoloration is present; hot water draws sediment from your water heater and increases staining risk.
- Wear gloves if you need to handle severely discolored water and protect fabrics and finishes from staining.
Common Homeowner Questions
- Should I drink the water? No — avoid drinking until the water runs clear; use bottled water if unsure.
- How long will it take to clear? Often a few minutes to a few hours of flushing; longer if there is heavy sediment or if the service line is affected.
- Could this damage my appliances? Yes — sediment can stain clothes and reduce appliance life, so avoid using dishwashers and washing machines until clear.
If you find the issue is limited to hot taps, check your water heater for sediment — this is a common separate cause and worth discussing with a plumber if flushing the tank is needed. For patterns tied to usage or season, see Brown water only when hot water used.
For more related articles, see the Brown or Rust-Colored Water Events hub.