This story is part of CT Mirror Explains, an ongoing effort to distill our wide-ranging reporting into a "what you need to know" format and provide practical information to our readers.

Lead plumbing was banned in the United States in 1986, but new data assembled by Connecticut’s water utilities show there may still be thousands of lead pipes carrying water into homes, apartments and some schools.

The Connecticut Mirror obtained hundreds of reports from the state Department of Public Health that show there could be as many as 8,000 lead service lines connecting people’s homes to the large water mains that run under the streets.

The state’s community water systems, which supply more than three-quarters of the state’s population with drinking water, began sending out notices late last year warning homeowners and renters that their service line could contain the toxic metal.

Every public water system across the country is now required to identify and replace all of the remaining lead service lines within the next 10 years. In the meantime, however, many utility customers are questioning how to protect themselves and their families from potential lead exposure.

Here’s what you need to know.

What is a lead service line and what’s the concern? 

Service lines are the pipes that connect buildings to the larger water mains that run below many sidewalks and roads in Connecticut. Those lines can be made of all types of material, including plastic, copper, galvanized steel and lead.

Between the late 1800s and the 1930s, it was not uncommon for homebuilders and water utilities to use lead to make those plumbing connections. And in many parts of the country, lead was considered a viable option until the federal ban in 1986.

The issue with lead plumbing is that the metal can leach into the water that is running through the pipes. And that is a problem because no level of lead in the human body is considered safe.

In adults, elevated levels of lead can affect kidney function and can contribute to cardiovascular problems, and in children it can cause developmental delays, learning difficulties and behavioral problems. 

How many lead service lines remain in Connecticut and where are they located?

According to the data compiled by Connecticut’s community water systems, there could be nearly 8,000 lead service lines still in the ground — though that number is likely to change as officials continue to inspect homes and dig up old water lines.

Those lead lines are not distributed equally throughout the state, however. Some utilities are finding very little lead in their systems, while others are predicting that hundreds or thousands of homes, apartments and other buildings could be affected.

The initial data provided to the Connecticut Department of Public Health shows that places like Bridgeport, Waterbury, Willimantic, New London, Middletown and Greenwich contain significant numbers of lead service lines. Some utilities, however, are just beginning to assess how many lead lines might remain in their systems.

The number of lead service lines in a water system is largely dependent on what years the public water system was built and what materials the utilities used over their history to make service connections.

How do I know if I have a lead service line?

Many utilities have created maps that allow water customers to search their address to learn whether they have a lead service line or not. Aquarion Water, Connecticut Water Company and many of the state’s larger municipal water systems, have links to those maps online.

CT Mirror created a search tool for the 60 largest water systems in the state.

The new federal regulations required utilities to send out notices to customers if they suspected that the service line contained lead or if they were unsure what material the service line is made of.

Some utilities are also soliciting help from their customers in identifying lead service lines. Many utility companies have asked customers to take photos of their water lines where they enter the basement or crawl space.

And they’ve provided step by step guides, like this one, for how to investigate what material was used for their service line.

Why are officials investigating these lines now and what are they going to do about them?

While lead plumbing was banned in the mid 1980s, the push to remove older lead service lines did not gain traction until after the water crisis in Flint, Michigan, in 2014.

That crisis was created when officials in Flint changed the source of the city’s drinking water, and it resulted in service lines and other plumbing leaching significant amounts of lead into people’s tap water.

To try to prevent similar public health emergencies, federal officials adopted new federal regulations last year requiring every utility serving more than 25 people to identify how many lead lines they have and to replace all of those lines in the next 10 years.

The U.S. Environmental Protection Agency estimates there could be between 6 million to 10 million still in use throughout the United States.

Replacing all of those service lines is likely to be an expensive and time-consuming process. In the meantime, most utilities will continue to treat their water with corrosion inhibitors — compounds that help prevent plumbing from leaching large amounts of lead into people’s tap water.

What precautions can I take if my home has a lead service line? 

The Connecticut Department of Public Health and many of the state’s water utilities are advising customers with suspected or confirmed lead service lines to take several precautionary steps to limit their potential exposure.

They are advising people to clean out the aerators on their sinks. Those are the small screens that are on the tips of most kitchen and bathroom faucets.

They are also encouraging people to run the water for several minutes before using the water for cooking or drinking.

The best way to protect against lead exposure, however, is a water filter that is certified to remove lead from drinking water. You can learn more about that filter certification here.