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Massachusetts Water Resources Authority

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In a long-sought public health victory, the Massachusetts Water Resources Authority’s program to reduce lead and copper levels at consumers’ taps has reached compliance with federal standards. Since 1992 lead levels in worst case samples of tap water from across the MWRA metro Boston service area have dropped significantly. With two rounds of testing in 2002 showing further declines, MWRA has met the federal Lead and Copper Rule for the first time.

In 1996 MWRA constructed an interim water treatment facility in Marlborough to control the corrosivity of the metro Boston water supply. While the water supply is basically lead-free, some consumers have lead pipes and fixtures inside their homes that leach lead into water sitting for long periods in pipes. MWRA began altering the pH and alkalinity of the water in 1996 for corrosion control and made several additional changes to optimize the system over the next six years.

"After years of hard work to carefully optimize water chemistry, MWRA’s treatment operators have overcome the older plumbing systems in many homes to provide safe drinking water at the tap," said MWRA Executive Director Frederick A. Laskey. "Combined with the MWRA’s ongoing water tunnel, treatment and storage projects to improve water system reliability and security, these improvements at the tap are the biggest advances in the regional water supply for many decades."

MWRA is now in compliance with the federal Lead and Copper Rule, with results below Action Levels for the required two consecutive sampling rounds.

Data from September 2002 sampling showed that 92 percent of the targeted high-risk homes had lead levels below the Action Level of 15 parts per billion (ppb). The federal standard requires that at least 90 percent of sample results are below this Action Level. The 90th percentile of lead results was 11.3 ppb, the lowest since testing began in 1992 when the 90th percentile result was 71 ppb. Copper levels have always been below the federal Action Level of 1,300 ppb, but reached their lowest levels this year.

MWRA is constructing the new Walnut Hill Water Treatment Plant in Marlborough to serve 2.2 million customers in metro Boston beginning in 2005. The treatment plant will use the powerful disinfectant ozone gas instead of chlorine, and incorporate new corrosion control facilities. Construction of the plant is now at 66% complete.

MWRA is constructing the new Walnut Hill Water Treatment Plant in Marlborough to serve 2.2 million customers in metro Boston beginning in 2005. The treatment plant will use the powerful disinfectant ozone gas instead of chlorine, and incorporate. Construction of the plant is now at 66% complete.

Service Area: The following towns are receiving full water supply from the MWRA and are covered by the MWRA's Lead & Copper Rule testing program:

Background Information

In 1992, the United States Environmental Protection Agency's (EPA) Lead and Copper Rule for drinking water went into effect. Lead or copper in tap water is primarily due to corrosion of plumbing system components within buildings. Plumbing components include copper pipes, lead-based solder used to join segments of copper pipe, and faucets made from brass that contains lead.

The rule sets action levels for lead and copper in standing samples collected from faucets with high risk for elevated lead and copper levels. The action level for lead is 15 micrograms per liter (µg/L) of water or 15 parts per billion (ppb). This compares to 1/10 of one teaspoon of sugar in 10,000 gallons of water. The copper action level is 1.3 milligrams per liter (mg/L) of water or 1.3 parts per million (ppm). If the monitoring results for a public water system exceed the action level for lead, the water system must conduct a public information campaign, and may be required to treat source water to control corrosion.

MWRA's water contains no detectable source of lead, but lead can leach into drinking water when water stands in contact with lead based solder or brass faucets containing lead in home plumbing. The Lead and Copper Rule required public water systems to monitor lead in standing water from homes most likely to have elevated levels of lead in drinking water.

Twice each year the MWRA has tested high-risk homes in the service area for lead in drinking water, drawing water samples that have been standing in the pipes for several hours. Over the last six years, these results exceeded the action level for lead in drinking water, triggering semi-annual education efforts to educate consumers on lead hazards.

Most cases of lead poisoning are from contact with peeling lead paint and lead paint dust. Although lead in tap water is rarely the single cause of lead poisoning, it can increase a person’s total lead exposure, particularly in infants who drink baby formula or concentrated juices that are mixed with water. The Environmental Protection Agency estimates that water can make up to 20% of a person’s total exposure to lead.