How does copper get into tap water?

Copper enters drinking water from household plumbing — copper pipes and fittings are the primary source. Like lead, the source water is typically copper-free; contamination occurs as water sits in copper pipes and corrodes the metal. Corrosive water (low pH, low alkalinity, high dissolved oxygen) dissolves more copper. The EPA's Lead and Copper Rule requires utilities to test for copper at customers' taps and treat for corrosion if the action level (1.3 mg/L) is exceeded at more than 10% of sampled sites.

Is copper in water dangerous?

Copper is an essential nutrient in small amounts, but too much causes gastrointestinal distress and, with chronic high exposure, liver and kidney damage. The EPA's MCL for copper is 1.3 mg/L (action level). At concentrations above 1 mg/L, water often has a noticeable metallic taste. Infants fed formula made with high-copper water are at the highest risk. Short-term exposure to very high copper (from new copper plumbing or highly corrosive water) can cause acute vomiting and diarrhea.

Does an NSF 53 filter remove copper?

Yes, NSF/ANSI 53 certifies certain filters for copper reduction. Most high-quality carbon block filters and all reverse osmosis systems certified to NSF 58 effectively reduce copper. The Aquasana AQ-5300+ under-sink filter and the Clearly Filtered pitcher are both NSF/ANSI 53 certified for copper reduction. Standard pitcher carbon (NSF 42) does not address copper.

How to Remove Copper from Drinking Water

Copper in Water: A Plumbing Problem with a Simple Filter Fix

Copper pipes were the gold standard of residential plumbing for most of the 20th century — durable, flexible, and resistant to bacteria compared to galvanized steel. But copper plumbing has a chemistry problem: water is inherently corrosive to copper, particularly water that's slightly acidic, softened, or high in dissolved oxygen.

The result is that millions of homes with copper plumbing see elevated copper in their first-draw water — the water that's been sitting in contact with pipes for hours. This is especially relevant in new homes where copper piping hasn't yet developed a protective carbonate coating (patina), and in areas where utilities treat source water aggressively enough to make it corrosive to metals.

Run Cold Water First in the Morning

If your home has copper plumbing, run the cold tap for 30–60 seconds before using water for drinking or cooking. This flushes the water that's been sitting in copper pipes overnight. A certified NSF/ANSI 53 filter eliminates the need for this step by capturing copper at the point of use.

Testing and Filtration for Copper

Copper levels vary significantly depending on water temperature, pH, and how long water has sat in your pipes. A standard tap water test ($79 at Tap Score) includes copper and gives you context for whether filtration is warranted.

For filtration, NSF/ANSI 53-certified carbon block filters are effective for copper at typical tap water concentrations (0.1–1 mg/L). Reverse osmosis removes copper more completely (95%+). The Aquasana AQ-5300+ under-sink filter ($149) is NSF 53 certified for both lead and copper — an efficient solution if both contaminants are a concern in your home.

For homes with very high copper (above 1 mg/L, often identifiable by a blue-green stain in sinks and tubs), the appropriate solution also involves addressing the root cause — checking water pH and working with your utility or a plumber to understand whether corrosion control treatment is needed or pipe replacement is warranted.

How to Remove Copper from Drinking Water

Copper in Water: A Plumbing Problem with a Simple Filter Fix

Testing and Filtration for Copper

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