Quick Answer:
If a metallic, coppery taste goes away after you run the tap, it most likely comes from water that sat in the pipes and picked up metal. Flushing brings fresh water from the main line. Time how long it takes for the taste to clear so you have a record — that timing helps decide if this is a plumbing issue or occasional stagnation.
Why This Happens
- Water sitting in copper pipes can dissolve small amounts of copper, especially if the water is slightly acidic or soft.
- Stagnant water near fittings, valves, or in seldom-used fixtures has more time to leach metal than water that moves regularly.
- Newer solder or brass fittings, or recent plumbing work, can temporarily increase metallic taste until protective layers re-form.
- Changes after a long absence from the home can cause a short-term taste — see Metallic taste after long vacation for related checks.
Step-by-Step What to Do
Step 1 — Verify and time the clearing
Fill a glass from the affected tap, note the taste, then run the cold water at normal flow and start a timer. Taste again at regular intervals (15, 30, 60 seconds, then every minute) and note the time when the taste is gone. Record the time and which faucet you used.
Step 2 — Compare faucets
- Try the same test on a different cold tap (bathroom vs kitchen) and on hot water. If only one faucet shows the taste, the problem is likely local to that fixture or its supply line.
- If the hot water tastes worse, the water heater or its anode might be contributing.
Step 3 — Clean the aerator and run water
Remove and inspect the faucet aerator for debris or corrosion, clean it, and reinstall. Run the tap until the taste clears and record that time. Do not assume this solving the issue permanently — flushing is a diagnostic and temporary step.
Step 4 — Note recent inactivity or changes
If the house was unused for days or weeks, or if there was recent plumbing work, that raises the chance the taste came from stagnant water or disturbed fittings. For similar situations, check guidance about Pennies smell from faucet as the symptoms can overlap.
Step 5 — Consider testing or utility help
- Contact your water provider to ask whether there are known supply issues or to request a basic water quality check.
- If you want a definitive answer, have the water tested for copper and pH by a certified lab. Bring your notes about which taps were affected and the time-to-clear you recorded.
Step 6 — Monitor and record
Keep a short log: date, faucet, time-to-clear, any visible staining (green/blue), and whether the taste returns. If the taste returns frequently or quickly after flushing, keep the log handy for a plumber or utility technician.
What Not to Do
- Do not rely on flushing as a permanent fix.
- Do not ignore a strong, persistent metallic taste — repeated exposure to high copper can be harmful, especially for children, pregnant people, or anyone with health issues.
- Do not attempt major plumbing work (soldering, replacing supply lines) unless you have the right tools and training; call a licensed plumber for invasive repairs.
When to Call a Professional
- The taste returns quickly after flushing or never fully goes away.
- You see blue-green stains on sinks, fixtures, or laundry — signs of elevated copper.
- Someone in the household feels unwell and you suspect water is involved.
- Water tests show copper above public-health guidance levels, or your utility recommends further investigation.
Safety Notes
- Do not drink water you suspect has a high metal content. Use bottled or known-safe sources until the issue is resolved.
- Boiling water does not remove dissolved metals like copper.
- If multiple people are ill or you have a vulnerable household member, stop using the water for drinking and food prep and contact your water utility or a professional promptly.
Common Homeowner Questions
- Is it safe to drink after the taste disappears? Usually yes if the taste is gone and the water tests normal; if in doubt, get a lab test or contact your utility.
- How long should I run the tap? Time it — many homes clear in 30 seconds to a few minutes, but larger plumbing systems or long service lines may take longer.
- Will boiling remove copper? No. Boiling may kill bacteria but does not remove dissolved metals; testing and source fixes are needed.
For more related articles, see the Metallic Taste, Copper Taste, or “Pennies” Smell hub.