Concerns about lead in District drinking water resurfaced this month with the publication of a new study that concluded that nearly 15,000 District homes where service pipes were replaced between 2004 and 2006 may still have some lead in their water. Officials with DC Water say the general water supply is safe - well below the Environmental Protection Agency's standard of 15 parts of lead per billion - but the study from the Centers for Disease Control and Prevention said some homes may still have high lead concentrations. Below, experts from the CDC, DC Water, EPA and George Washington University answer questions about drinking water and lead.

How can I check the lead level of my water?

Ask DC Water (202-354-3600) for a free lead test kit and information about your specific pipes. The agency will deliver a kit to you within three to five business days. Using the kit involves collecting several water samples in the provided bottles, which DC Water will then pick up. The agency will send the samples to a lab and get the results within four to six weeks, forwarding them to you several days later.

The CDC recommends that you use bottled or filtered water if you can until you know that your water does not have a lead concentration of 15 parts per billion or more. For those using tap water, it's important to try to lower the level of lead by taking such steps as running the cold water tap for at least two minutes before using it and making sure to use cold tap water, since preheating the water may cause lead to leach from lead-contaminated plumbing inside your home.

How much lead is too much? When should I worry?

The EPA action level of 15 parts per billion is the standard for what's okay in water. (Some experts believe even that may be too much; lead can build up in the body over time.) As for lead levels in the blood, "there is no known safe lead level," says Lynn Goldman, a pediatrician and the dean at George Washington University's School of Public Health and Health Services.

Why is lead such a health concern?

Lead can have lasting effects on mental and physical development, building up in your body for years. Lead poisoning can cause such symptoms as headaches, muscle weakness, anemia, behavioral problems, lethargy, difficulty focusing, metallic taste in mouth and digestive problems, according to the National Institutes of Health. Lead can damage kidneys, nerves and red blood cells.

Although lead poisoning affects all ages, children younger than 6 are most vulnerable because their brains are still developing. Small amounts of lead have been associated with a low IQ, hearing loss, hyperactivity and a tendency toward aggressive or violent behavior. A blood test is the only way to determine if you have lead poisoining.

When should I take my child to see the doctor?

The District's Department of Health recommends that children receive two blood-lead tests: the first between 6 and 14 months, the second between 22 and 26 months. Contact the department at 202-671-5000 to learn about blood-lead tests in your area. The CDC says Medicaid and many other health plans will cover the cost of this testing.

How is lead poisoning treated?

Lead poisoning can be difficult to treat. The first line of treatment is to identify and remove sources of the problem. That alone can often reduce lead concentrations. Children younger than 6 years old with very high lead levels will benefit from a therapy called chelation, says Goldman. This needs to be done under careful medical supervision.