Quick Answer:
Brown water that shows up only in spring or fall is usually caused by changes in flow and demand in the water system that disturb settled iron or mineral particles. It often clears after running cold taps for a few minutes or after the utility finishes seasonal flushing. Keep a simple log and check a few fixtures before assuming there’s a serious pipe problem.
Why This Happens
Seasonal changes (higher or lower water use, hydrant flushing, or distribution-system maintenance) change the speed and direction of water in mains and service lines. When flow patterns shift, iron oxide, sediment and mineral deposits that have settled can be stirred up and carried into your plumbing. That shows up as brown, tan, or rusty-colored water at taps.
Other common triggers in spring and fall include:
- Hydrant flushing by the utility or routine maintenance.
- Higher or lower neighborhood demand that alters flow velocity.
- Work on mains or valves that temporarily disturbs deposits.
If you recently had work done, compare symptoms to known situations like Brown water after replacing pipes and check if the utility performed any work that day. If the issue began right after a shutoff or repair, also compare with notes on Discolored water after main shutoff.
Step-by-Step What to Do
Step 1 — Observe and record
- Log dates when brown water appears and correlate with seasonal demand changes.
- Note which fixtures show discoloration (only hot, only cold, or both), what time of day it happens, and how long it lasts.
- Take a photo or small sample in a clear container for your records.
Step 2 — Compare fixtures and neighbors
- Check multiple cold water taps and an outside hose bib. If cold is clear and hot is brown, the water heater is likely the source.
- Ask a neighbor if they see the same discoloration; if they do, it points to a utility or main-line issue rather than your house plumbing.
Step 3 — Flush affected lines
- Run a cold tap at the lowest point in the house (such as a basement laundry sink or an outside faucet) for 5–10 minutes and watch for clearing.
- If hot water is brown, run a hot tap to see if it clears; if not, you may need to flush the water heater according to the manufacturer’s simple drain instructions or call a plumber to do it safely.
Step 4 — Contact the water utility
- Report the dates and your log. Utilities can tell you about planned flushing, repairs, or recent work that could explain seasonal discoloration.
- If the utility confirms system work, ask how long it typically takes to clear.
Step 5 — Document and monitor
- Keep your log for a few weeks. If the problem repeats every spring or fall and clears soon after, it’s likely seasonal sediment movement.
- If discoloration continues for several days, worsens, or appears outside seasonal periods, move to the “When to Call a Professional” steps below.
What Not to Do
- Do not assume corrosion if it only happens seasonally.
- Don’t immediately replace pipes because of a short, seasonal issue.
- Don’t use strong chemicals or do aggressive flushing without guidance — that can push particles deeper into fixtures or damage finishes.
- Don’t ignore documenting dates and fixture behavior; detailed notes make it easier to find the cause.
When to Call a Professional
- Discoloration persists for more than a few days after flushing or after the utility reports work in the area.
- Brown water is present at all times and in both hot and cold lines, or you notice reduced flow or leaks along with discoloration.
- Hot-water-only discoloration that doesn’t clear after flushing the water heater, or if you’re unsure how to safely flush your heater.
- If you have vulnerable household members (infants, elderly, immunocompromised), call for help sooner rather than later.
Safety Notes
- Brown or rusty water is usually an aesthetic and staining issue rather than an acute health hazard, but avoid drinking or cooking with visibly discolored water until it clears.
- If in doubt, use bottled water for drinking and food preparation until a clear sample is confirmed.
- Avoid using discolored water in washing machines or dishwashers when possible; it can stain fabrics and surfaces.
- If you suspect contamination beyond mineral/iron particles (unusual odor, oily sheen, or known main breach), stop using the water and contact the utility immediately.
Common Homeowner Questions
- Why does it happen only in spring and fall? — Seasonal shifts in flow and routine utility work disturb settled sediments, so discoloration shows up more often during these periods.
- Will running the tap always fix it? — Often yes; running cold taps at a low point for several minutes clears most sediment. If it doesn’t clear, further investigation is needed.
- Is discolored water dangerous to drink? — Typically it’s a staining/mineral issue, but don’t drink it until it’s clear; use bottled water if unsure or if vulnerable people are in the home.
For more related articles, see the Brown or Rust-Colored Water Events hub.