How Lead Gets into Drinking Water

• Lead can enter drinking water when service pipes that contain lead corrode.

• The most common problem is with brass or chrome-plated brass faucets and fixtures with lead solder, from which significant amounts of lead can enter into the water, especially hot water. Homes built before 1986 are more likely to have lead pipes, fixtures and solder.

• The Safe Drinking Water Act (SDWA) has reduced the maximum allowable lead content.

• The SDWA was implemented in 1974 with the most recent amendments, including the Lead and Copper Rule (LCR), implemented in 2015.

• To address corrosion of lead and copper into drinking water, EPA issued the Lead and Copper Rule (LCR) under the authority of the SDWA. Corrosion is a dissolving or wearing away of      metal caused by a chemical reaction between water and your plumbing. A number of factors are involved in the extent to which lead enters the water, including:

• the chemistry of the water (acidity and alkalinity) and the types and amounts of minerals in the water,
• the amount of lead it comes into contact with, o the temperature of the water,
• the amount of wear in the pipes, o how long the water stays in pipes, and
• the presence of protective scales or coatings inside the plumbing materials.
   

Is there a safe level of lead in drinking water?

• The Safe Drinking Water Act requires EPA to determine the level of contaminants in drinking water at which no adverse health effects are likely to occur.

• These non-enforceable health goals, based solely on possible health risks, are called maximum contaminant level goals (MCLGs).

• EPA has set the maximum contaminant level goal for lead in drinking water at zero because lead is a toxic metal that can be harmful to human health even at low exposure levels.

• Lead is persistent, and it can bio accumulate in the body over time. 

Adverse health effects of lead CHILDREN - Even low levels of lead in the blood of children can result in:

• Behavior and learning problems.

• Lower IQ and hyperactivity.

• Slowed growth.

• Hearing problems.

• Anemia.

PREGNANT WOMEN

Lead can accumulate in our bodies over time, where it is stored in bones along with calcium. During pregnancy, lead is released from bones as maternal calcium and is used to help form the bones of the fetus. This is particularly true if a woman does not have enough dietary calcium. Lead can also cross the placental barrier exposing the fetus to lead. This can result in serious effects to the mother and her developing fetus, including:

• Reduced growth of the fetus.

• Premature birth. 

ADULTS

Lead is also harmful to adults. Adults exposed to lead can suffer from:

• Cardiovascular effects, increased blood pressure and incidence of hypertension.

• Decreased kidney function.

• Reproductive problems (in both men and women). 

Can I shower in lead-contaminated water?

• Yes. Bathing and showering should be safe for you and your children, even if the water contains lead over EPA's action level.

• Human skin does not absorb lead in water. 

Having your water tested for lead

• Since you cannot see, taste, or smell lead dissolved in water, testing is the only sure way of telling whether there are harmful quantities of lead in your drinking water.

• A list of certified laboratories is available from your state or local drinking water authority. Contact your water supplier as they may have useful information, including whether the service connector used in your home or area is made of lead. 

Take Measures to Reduce Lead in Drinking Water at Home

• Flush your pipes before drinking

• The more time water has been sitting in your home's pipes, the more lead it may contain. Anytime the water in a particular faucet has not been used for six hours or longer, "flush" your cold-water pipes by running the water until it becomes as cold as it will get. This could take as little as five to thirty seconds if there has been recent heavy water use such as showering or toilet flushing. Otherwise, it could take two minutes or longer. Your water utility will inform you if longer flushing times are needed to respond to local conditions.

• Only use cold water for eating and drinking

• Use only water from the cold-water tap for drinking, cooking, and especially for making baby formula. Hot water is likely to contain higher levels of lead. Run cold water until it becomes as cold as it can get.

• Boiling water will NOT get rid of lead contamination

• Use water filters or treatment devices:

• Many water filters and water treatment devices are certified by independent organizations for effective lead reduction.
• Devices that are not designed to reduce lead will not work.

Source:  https://www.epa.gov/ground-water-and-drinking-water/basic-information-about-lead-drinking-water