Pennies smell after pressure surge

Quick Answer:

If you notice a pennies or metallic smell right after a pressure surge, small bits of copper oxide or loosened mineral scale can be suspended in the water. Check pressure behavior first: attach a pressure gauge and log surges at a convenient test port or outdoor hose bib to see how large and how often the spikes are. Flush faucets and document results; if the smell persists or you see very high spikes, contact a licensed plumber.

Why This Happens

• Sudden pressure surges (water hammer or upstream supply events) can scour interior pipe surfaces. If pipes have copper or copper-bearing scale, tiny particles or dissolved copper can be released into the water, producing a metallic or “pennies” odor.
• Changes in chemistry—like oxygenating stagnant water—can temporarily change taste and smell until the disturbed material is flushed out. For related situations after winterization see Metallic taste after winterization.
• Pressure spikes can also reveal an underlying pressure-regulator or expansion tank problem that allows frequent high-pressure events.

Step-by-Step What to Do

1. Note timing and scope

• When did the surge happen? Time of day, appliances in use, or municipal work nearby can be clues.
• Which fixtures show the smell — hot only, cold only, or both?

2. Attach a pressure gauge and log surges

• Install a simple screw-on pressure gauge at an outdoor hose bib or at a test port near the main shutoff. Turn a faucet on to stabilize and read the gauge.
• Log readings over a day or two, noting baseline pressure and any short-term spikes. Typical household static pressure is around 50–60 psi; repeated spikes above 80–100 psi are a concern.

3. Flush affected fixtures

• Run cold water from the affected fixture for several minutes to clear suspended particles. If the smell clears, it often indicates transient contamination from the surge.
• After flushing, check if the smell returns quickly or stays away. Many homeowners see the smell disappear after thorough flushing; this is related to why Copper taste disappears after flushing in similar situations.

4. Inspect visible components

• Look for loose fittings, corroded valves, or signs of recent plumbing work. Check the pressure-reducing valve (PRV) for obvious leaks or damage—but don’t change settings yet.

5. Record and decide

• Keep your pressure log, notes on which fixtures were affected, and results of flushing. If the problem is short-lived and clears with flushing, monitor for recurrence. If surges continue or smells persist, escalate to a professional.

What Not to Do

• Do not adjust PRV settings blindly. Changing regulator settings without proper diagnosis can cause other issues and may void warranties.
• Do not assume discoloration or smell automatically means widespread corrosion; test and observe first before replacing pipes.
• Do not use chemical treatments or home remedies without guidance from a water professional—some chemicals can react with pipe metals.

When to Call a Professional

• If pressure logs show repeated large spikes or sustained high pressure above normal ranges.
• If flushing does not remove the metallic smell or if water appears discolored after flushing.
• If you find damaged or leaking valves, a failing PRV, or if you’re unsure how to safely install a gauge or interpret readings.

Safety Notes

• When attaching a pressure gauge use an accessible hose bib or test port and follow the gauge manufacturer’s instructions. Release water pressure before removing fittings.
• Be cautious when working near hot-water lines to avoid scalding. Run cold-water tests if you’re concerned about heat.
• If you suspect contamination beyond cosmetic taste or smell (like health concerns), stop using the water for drinking and contact your local health department or a licensed plumber for testing.

Common Homeowner Questions

• Will the smell go away on its own?
  Often yes, after flushing and a few uses; persistent smell needs monitoring or professional help.
• Can a pressure surge ruin pipes?
  Repeated severe surges can accelerate wear and cause leaks; occasional spikes are less likely to cause immediate failure but should be checked.
• Is this a health risk?
  A brief metallic taste is usually an aesthetic issue; if it persists or you have health concerns, get the water tested and consult a pro.