Drinking water in one out of eight Denver homes with lead plumbing may be contaminated with lead — a health hazard that causes brain and nerve damage, especially in children.
This result from recent tests has forced Denver Water to warn residents and to take action to protect people.
The lead concentrations measured in samples from 60 homes exceeded the federal drinking water standard of 15 parts per billion by as much as 3.8 times.
The 13 percent of Denver homes that had high lead levels, up from 8 percent of homes in 2011, is the highest percentage logged in 12 years, according to Denver Water data provided to the Denver Post.
“People should try to limit their exposure and reduce it to the level they can,” said Dr. Lisa Miller, the Colorado Department of Public Health and Environment director of disease control and environmental epidemiology.
Doctors “do see elevated blood levels (of lead) in Denver and other counties around Colorado,” Miller said. She recommended testing of low-income children, who are especially at risk for exposure.
While sources of Denver water in the mountains traditionally have been safe, more than half of homes may have lead pipes — either inside the houses or connecting them to Denver Water mains. The lead can be disturbed if pipes are cut or corroding, which lets it leach into water that eventually flows from taps.
Other cities in New York, Oregon, Kentucky and Massachusetts have wrestled with lead contamination of water in recent years. Boston offers incentives to help homeowners replace pipes from the house to the main.
The Environmental Protection Agency requires water utilities to take action when required annual tests show more than 10 percent of homes with lead pipes have water containing lead above 15 ppb.
EPA officials this week issued a statement saying they are “encouraged that Denver Water is taking appropriate action in response to eight recent tap water samples that exceeded drinking water action levels for lead.”
Denver Water teams tested household water between June and August. They collected water from 60 homes built between 1880 and 1989 that still have lead plumbing. Eight had lead in water exceeding the 15 ppb standard, which the EPA set as the lowest level that reasonably could be enforced. The tests showed concentrations of 17, 17, 18, 19, 23, 29, 31 and 57 ppb. These results came from homes built before 1920.
This month, all 1.3 million metro residents served by Denver Water must be notified and advised of precautions they can take. Those precautions will include: drawing cold water for drinking, cooking and preparing baby formula; letting faucets run a bit before drawing water to flush out lead; considering use of a filter and having household water tested. Denver Water now must test household water every six months, with the minimum sample size increased to 100 homes from 50. Utility officials also are required to test water elsewhere in the distribution system to verify levels of lead and copper in source waters and must conduct a water chemistry study of corrosion.
“It’s going to take a fair amount of hard work over some time here to truly evaluate the situation,” said Ron Falco, drinking water program manager for CDPHE’s Water Quality Control Division.
Lead becomes a health hazard when it builds up in the body. Too much lead can damage the brain, nerve system, red blood cells and kidneys. Children under 6 and pregnant women are especially vulnerable. Even low levels of lead can cause learning and behavior problems.
Denver residents living in homes built in the mid-1950s or earlier are likely to have lead pipes — which belong to homeowners — linked to the mains.
Federal census data show there are about 61,600 houses in Denver County built before 1939 — about 24 percent of all homes — and that 71,700 homes were built between 1940 and 1959, or about 28 percent of all homes.
Just having lead plumbing does not mean water is tainted.
“If you have lead plumbing in your house, you need to follow some protocols we’ve developed and laid out for that,” said Tom Roode, Denver Water’s director of operations and maintenance.
The costs of replacing plumbing, including connectors, fall to homeowners, not Denver Water, Roode said. “As the lead plumbing disappears, the problem will eventually go away.”
Denver Water officials say they don’t see this as a growing problem, despite data showing 13 percent of homes with lead plumbing are affected — the highest since 2000. They point out that calcium and other minerals occurring naturally in mountain source water can insulate lead pipes and prevent contact with water.
“The aging factor does not contribute to it at all,” Roode said. “The more coating there is on the pipes, the more insulation there is between water and the lead. The key, what can be a problem, is disturbing the lead to where lead can be in contact with water.”
Bruce Finley: 303-954-1700, twitter.com/finleybruce or bfinley@denverpost.com
