A metallic taste or recurring blue-green stains can be a clue that copper is entering your tap water. In many homes, the source is not the treatment plant but corrosion of copper-containing pipes, fittings, and fixtures after water enters the plumbing system.
Where Does Copper in Drinking Water Come From?
Copper occurs naturally in rocks, soil, water, and food. Small amounts are necessary for normal body functions, and diet is generally the primary source of copper for most people.
In drinking water, however, elevated copper commonly comes from corrosion of plumbing materials. Copper can dissolve after treated water leaves the utility and comes into contact with copper pipes, brass fixtures, valves, fittings, or other copper-containing components.
How much copper enters the water depends on several interacting factors:
- water acidity and alkalinity;
- mineral content and other aspects of water chemistry;
- water temperature;
- the age and condition of plumbing;
- how long water remains stagnant in pipes; and
- protective scales or coatings that have formed inside the plumbing.
This is why two neighboring homes served by the same utility can have different copper concentrations at the tap.
What Are the Signs of Copper in Water?
Possible clues include a metallic taste and blue-green staining around sinks, tubs, drains, or plumbing fixtures. Greenish deposits on copper-containing plumbing can also indicate corrosion.
These signs do not indicate the concentration, and their absence does not prove that copper is low. Laboratory testing is the reliable way to determine how much copper is present.
EPA's Copper Action Level: What 1.3 mg/L Actually Means
Copper is regulated differently from contaminants that have a conventional Maximum Contaminant Level measured at the treatment plant. EPA uses a treatment-technique framework under the Lead and Copper Rule because copper often enters drinking water through corrosion after water reaches the distribution and household plumbing system.
| EPA value | Copper level | What it means |
|---|---|---|
| Maximum Contaminant Level Goal (MCLG) | 1.3 mg/L | Non-enforceable health goal. |
| Action Level | 1.3 mg/L | Triggers additional water-system requirements when the 90th-percentile tap result exceeds this level. |
An action-level exceedance occurs when copper is above 1.3 mg/L in more than 10% of required customer-tap samples—in other words, when the system's 90th-percentile copper result is above 1.3 mg/L.
Can Copper in Drinking Water Affect Health?
Copper is necessary in small amounts, but high exposure can cause adverse effects. EPA identifies gastrointestinal effects such as nausea, vomiting, stomach distress, and intestinal distress as concerns from elevated short-term exposure. Long-term exposure at sufficiently high levels can affect the liver and kidneys.
People with Wilson's disease, a rare inherited disorder that affects copper metabolism, can be particularly sensitive to copper exposure and should follow medical guidance appropriate to their condition.
Which Homes May Be More Likely to Have Elevated Copper?
Elevated copper is not limited to old houses. Testing may be particularly useful when a home has:
- copper pipes, service lines, or copper-containing fittings;
- newly installed copper plumbing;
- corrosive or low-pH water;
- water that frequently sits unused for many hours;
- seasonal or prolonged vacancy;
- persistent blue-green staining; or
- a recurring metallic taste.
New copper plumbing can sometimes release more copper while protective scale develops. Older plumbing can also contribute depending on corrosion conditions. Age alone cannot predict the result.
How to Test Drinking Water for Copper
If you receive public water, begin with your utility's Consumer Confidence Report. The report provides useful system-level information, including the most recent 90th-percentile lead and copper results where applicable, but it cannot determine the copper concentration at your particular faucet.
For household-specific testing, use a state-certified or otherwise appropriately accredited drinking-water laboratory and follow its sampling instructions exactly.
First-Draw vs. Flushed Samples
A first-draw sample collected after water has remained stagnant in the plumbing can help evaluate copper contributed by the plumbing system. Depending on your goal, a laboratory or water professional may also recommend a flushed sample for comparison.
Do not improvise the sampling protocol if you are trying to compare your result with a regulatory or health benchmark. Stagnation time, faucet selection, sample volume, and flushing can materially change the result.
What Should You Do if Copper Is Elevated?
The best response depends on whether the copper originates primarily from plumbing corrosion, source water, or both. For household plumbing, practical exposure-reduction steps can include:
- Use cold water for drinking and cooking. Heat cold water separately rather than starting with hot tap water.
- Flush stagnant water. If water has been sitting for hours, run the cold tap until the water becomes noticeably colder or follow local utility guidance before using it for drinking or cooking.
- Investigate corrosion. Persistent copper problems may require evaluation of pH, alkalinity, plumbing materials, or corrosion-control conditions.
- Repair or replace contributing plumbing. A licensed plumber can help identify fixtures or plumbing components involved.
- Use contaminant-specific filtration when appropriate. Verify evidence of copper reduction for the specific filter element or treatment device.
Does Boiling Remove Copper?
No. Boiling does not remove dissolved copper. Because water evaporates while copper remains behind, prolonged boiling can increase the concentration of dissolved substances in the remaining water.
Can Berkey® Filters Reduce Copper?
Yes. Both Black Berkey® Elements and Phoenix Gravity New Millennium Edition™ Filter Elements have independent laboratory evidence for copper reduction under documented test conditions.
| Filter element | Copper challenge | Reported effluent | Documented result |
|---|---|---|---|
| Black Berkey® Elements | 3,150 µg/L | <2 µg/L | >99.9% reported in Envirotek Report #14-260 at pH 6.5 and pH 8.5 |
| Phoenix Gravity New Millennium Edition™ | 2,000 µg/L | 40.8 µg/L | 97.96% calculated from the April 2026 Atom Testing Laboratory result |
The Black Berkey® report tested copper at pH 6.5 and pH 8.5 and found effluent below the laboratory detection limit under both conditions. Phoenix's current independent testing also provides copper-specific data, showing a reduction from 2,000 µg/L to 40.8 µg/L.
These are independent laboratory results; they should not be described as NSF copper-reduction certifications. Actual performance can vary with water chemistry, starting concentration, element condition, service volume, flow, and other factors.
Many existing Berkey® owners continue to use Black Berkey® Elements. When replacement is needed, Phoenix Gravity is the current compatible replacement option through normal authorized U.S. distribution. Review the Berkey® Filter Test Results and Berkey® Replacement Filter Guide before choosing an element.
Choosing a Berkey® System Size
The system determines storage capacity; copper-reduction performance depends on the installed filter element.
| System | Capacity | Typical Fit | Product |
|---|---|---|---|
| Travel Berkey® | 1.5 gallons | Singles and couples | View Travel Berkey® |
| Big Berkey® | 2.25 gallons | Many households | View Big Berkey® |
| Royal Berkey® | 3.25 gallons | Larger households | View Royal Berkey® |
| Imperial Berkey® | 4.5 gallons | Higher daily use | View Imperial Berkey® |
| Crown Berkey™ | 6 gallons | Large households and group use | View Crown Berkey™ |
Frequently Asked Questions
Does copper usually come from household plumbing?
Yes, plumbing corrosion is a major source of copper in drinking water, although copper can also occur in source water. Pipes, fittings, valves, and fixtures can release copper depending on water chemistry and contact time.
What does EPA's 1.3 mg/L copper action level mean?
The Lead and Copper Rule uses 1.3 mg/L as the copper action level. A water system exceeds it when the 90th-percentile result from required tap sampling is above 1.3 mg/L. It is not a conventional MCL applied to every glass of water.
What causes blue-green stains?
Copper corrosion can create blue-green deposits on sinks, tubs, drains, or plumbing fixtures. The staining can suggest a copper problem but does not reveal the concentration in drinking water.
Should I use hot tap water for cooking?
Cold tap water is generally preferred for drinking and cooking when metal leaching is a concern. Heat cold water separately when hot water is needed.
Does boiling remove copper?
No. Boiling does not remove dissolved copper and can concentrate nonvolatile substances as water evaporates.
Can Black Berkey® Elements reduce copper?
Yes. Envirotek Report #14-260 challenged Black Berkey® Elements with 3,150 µg/L copper and reported effluent below 2 µg/L, with greater than 99.9% reduction under the evaluated conditions.
Can Phoenix Gravity elements reduce copper?
Yes. Independent April 2026 testing reported copper at 2,000 µg/L before filtration and 40.8 µg/L after filtration, corresponding to 97.96% calculated reduction under the documented conditions.
Related Drinking Water Guides
Final Thoughts
Copper in drinking water is often a plumbing-corrosion problem rather than a source-water problem. A metallic taste or blue-green stains can warrant investigation, but only testing can tell you the concentration in your tap water.
If copper is elevated, first identify and address the source. Flushing stagnant water, using cold water for consumption, correcting corrosive water conditions, and repairing contributing plumbing may all be part of the solution. Point-of-use filtration can provide an additional treatment option when the exact filter has documented copper-reduction performance.