Lead & copper

What lead and copper are

Lead and copper are both metals used for decades in the pipes and fixtures that carry water into homes. Copper became the standard material for household plumbing, valued because it resists corrosion and lasts for years. Lead was used in service lines, in the solder that joined copper pipes, and in the brass of older faucets and valves.

The key difference is what each one does to you. Copper is an essential nutrient your body needs in small amounts, and problems arise only at higher doses. Lead serves no purpose in the body at all. The CDC treats any amount in a child's blood as a concern, which is why the metal that once seemed convenient is now the one utilities and homeowners work hardest to keep out of the water.

Neither metal usually starts in the source water. The EPA notes that lead enters drinking water mainly through corrosion, the chemical reaction that happens when water sits in contact with lead-bearing plumbing and dissolves a small amount of the metal.

The conditions inside the pipe drive it. Water that is acidic or low in minerals pulls more metal from the plumbing, and water that sits still overnight or over a weekend picks up more than water that moves. Copper leaches the same way, dissolving from copper pipes when water is corrosive or stagnant. This is why the problem is invisible at the treatment plant and specific to each home. The utility controls the water. Your plumbing controls what the water becomes on the way to your tap.

How they enter the home

Lead reaches your water through 4 main paths, and all of them sit on the house side of the meter. The lead service line is the largest source. This is the pipe that connects a home to the water main under the street, and where it is made of lead, it puts the metal in direct, constant contact with every drop that flows through.

Solder is the next culprit. Plumbers used lead solder to join copper pipes for generations, until the 1986 amendments to the Safe Drinking Water Act banned lead solder and lead pipe in plumbing that carries drinking water. Homes built or plumbed before that ban are the ones most likely to hold lead in their joints. Older brass fixtures add a third path, since faucets and valves manufactured before stricter limits took effect can contain lead that leaches into standing water. Copper enters through the copper pipes themselves, corroding into the water under the same conditions that free the lead. The age of your home is the clearest clue to your risk, because it points directly to what your plumbing is made of.

Children carry the greatest danger from lead. The CDC states there is no safe blood lead level in children, and even low levels are linked to lower IQ, attention problems, learning difficulties, and slowed development. Young children absorb lead more readily than adults and take in more relative to their body size, so the same water affects them far more.

Infants fed formula mixed with tap water face a distinct risk, since their entire diet can run through contaminated water during the months their brains develop fastest. Pregnant women are the other high-risk group. Lead crosses the placenta, so exposure during pregnancy reaches the developing fetus and is linked to reduced growth and premature birth. Copper poses less risk to most people, but infants are more sensitive to it as well, and people with Wilson's disease, a genetic condition that prevents the body from clearing copper, must avoid elevated levels entirely.

What lead and copper do to the body

Lead does its damage quietly and without a taste, smell, or color to warn you. In children, the CDC links it to lasting harm to the brain and nervous system, slowed growth, hearing and speech problems, and behavioral and learning issues that can follow a child for life. The effects can appear at blood levels once considered acceptable, which is why the agency dropped the idea of a safe threshold entirely.

Adults are not spared. Long-term lead exposure is associated with high blood pressure, kidney damage, and reproductive problems, the EPA reports. Copper works faster and more visibly at high doses. Short-term exposure to elevated copper can cause nausea, vomiting, stomach cramps, and diarrhea, and long-term exposure at high levels can damage the liver and kidneys, especially in people who cannot process it normally. The contrast matters: copper often announces itself through illness or a metallic taste, while lead gives no signal at all until the harm is already done.

How to test and what the levels mean

Testing is the only way to know what your tap water holds, because you cannot see, taste, or smell lead. Many public water utilities offer free or low-cost testing to their customers, and a certified laboratory can run a sample for a modest fee. The EPA recommends using a state-certified lab and collecting a first-draw sample from water that has sat in the pipes for at least six hours, since that is when metal levels are highest.

The federal rules set the benchmarks. The Lead and Copper Rule, first issued by the EPA in 1991, requires water systems to control corrosion and monitor for both metals at customer taps. It sets an action level of 15 parts per billion for lead and 1.3 parts per million for copper. When more than 10% of sampled taps exceed those levels, the utility must take steps such as treating the water to reduce corrosion, informing the public, and replacing lead service lines. The action level is not a safety threshold. The EPA sets the health goal for lead at zero, consistent with the CDC's position that no amount is safe for children.

What a household can do

Find out what your service line is made of first, because it is the single largest source of lead. Utilities now publish service line inventories, and many let you look up your address online to learn whether a lead line runs to your home. Your annual Consumer Confidence Report also lists lead monitoring results for the system.

Reduce your exposure while you wait for results or a line replacement. Run the tap for 30 seconds to two minutes before drinking or cooking after water has sat overnight, since flushing clears the water that absorbed the most metal. Use cold water for drinking, cooking, and mixing infant formula, because hot water dissolves lead faster. Never boil water to remove lead, since boiling only concentrates it as water evaporates. Test your water through a certified lab, and if lead is present, use a filter certified to NSF/ANSI Standard 53 for lead removal, and replace the cartridge on schedule. Clean faucet aerators regularly to clear trapped particles. If you have a lead service line, ask your utility about replacement programs, and replace older brass fixtures and any lead solder during renovations. For infants, consider using bottled or filtered water for formula until a test confirms your tap is safe.