Copper
Summary: Copper usually enters water from your home’s plumbing. When water is corrosive or sits in copper pipes, small amounts can dissolve, leading to blue-green stains, metallic/bitter taste, and sometimes pinhole leaks. Testing shows whether corrosion control or point-of-use treatment is needed.
Where does copper come from?
- Copper pipes and fittings: The most common source is your own plumbing, especially where water sits overnight.
- Leaded solder (older homes): Solder used before modern standards can contribute both copper and trace lead.
- Brass valves/fixtures: Brass is an alloy that contains copper; corrosion can release copper into water.
Why homeowners should care
Copper is essential in tiny amounts, but elevated levels are undesirable—especially for infants and sensitive individuals. Blue-green stains on sinks/tubs and a metallic or bitter taste are common clues. The good news: copper issues can often be fixed with corrosion control and/or point-of-use treatment.
Action levels vs health limits
Copper is evaluated with an action level under the Lead and Copper Rule. An action level is a trigger for corrosion-control steps—not a guarantee of safety at or below that number. If copper is detected at elevated levels, reduce exposure and address corrosion.
How we test
HealthWaterLab recommends collecting both first-draw (after water sits in pipes, typically overnight) and flushed samples (after running the tap). This shows how much your plumbing contributes and helps choose the right fix. Pairing results with pH, alkalinity, hardness, and temperature gives a fuller corrosion picture.
Reducing copper in your water
- Corrosion control: Adjust water chemistry (pH/alkalinity) and avoid aggressive conditions. Some systems use corrosion-inhibitor dosing (e.g., orthophosphate) under professional guidance.
- Point-of-use filtration at the kitchen sink: Reverse osmosis (RO) or certified cartridges for copper reduction provide low-copper water for drinking/cooking.
- Smart flushing: Run the tap until water turns cold and steady before drinking/cooking, especially after periods of stagnation.
- Plumbing updates: Replace failing sections, leaded solder, or problematic mixed-metal joints; avoid using hot water for drinking/cooking.
Recognizing symptoms
- Blue-green stains on fixtures, tubs, or around faucet aerators.
- Metallic/bitter taste, especially in first-draw water.
- Pinhole leaks in copper lines, often linked to corrosive water or flow conditions.
FAQ
Why are there blue-green stains on my sinks?
That’s a classic sign of copper dissolving and re-depositing. It often points to corrosive water (low pH/alkalinity) or long stagnation time in copper pipes.
Does boiling remove copper?
No. Boiling won’t remove dissolved metals and can concentrate them. Use reverse osmosis (RO) or certified filters for copper reduction.
Can a water softener fix copper?
Not reliably. Softeners target hardness (calcium/magnesium). For copper, focus on corrosion control and/or RO at the kitchen tap.
Which sample should I collect—first-draw or flushed?
Both. First-draw captures water that sat in the pipes (worst-case). Flushed shows conditions after running the tap and helps separate plumbing effects from source water.
Is hot water okay for drinking or baby formula?
No. Hot water dissolves metals more readily. Always use cold water for cooking and formula, and heat it separately if needed.
How long should I flush the tap?
Until temperature turns cold and steady. Time varies by plumbing layout—longer runs or larger homes take more time. After flushing, fill containers for the day’s use.
My copper result is high—do I need whole-home treatment?
Usually no. Since copper exposure is mainly from drinking/cooking, point-of-use RO at the kitchen tap is often sufficient. Address corrosive water and plumbing issues to protect fixtures and avoid leaks.
Will a fridge or pitcher filter remove copper?
Only if it’s certified for metal reduction. Check the certification. RO is a dependable option if you’re unsure.
Why did my copper level change since last year?
Changes in pH/alkalinity, temperature, water use, or new plumbing can all affect corrosion. That’s why periodic testing and trend tracking help.
Should I test for lead too?
Yes. Homes with copper pipes and older solder/fixtures can also have lead. Testing both provides a complete picture.
Ready to test? Order a copper (and lead) tap-water kit with step-by-step sampling instructions at HealthWaterLab.com.