Environmental Progress - Fall 2001

New Standard For Arsenic In Drinking Water Confirmed

Supplies must meet limit of 10 parts per billion by January 2006

After months of controversy and re-study, U.S. EPA has announced that 10 parts per billion (ppb) will be the new standard for arsenic in drinking water, a maximum contaminant level that must be met by January 2006.

A standard of 10 ppb was announced last January, then suspended by U.S. EPA to allow additional independent reviews. The decision to remain with the 10 ppb limit was announced by U.S. EPA Oct. 31. The previous MCL for arsenic, 50 ppb, was set in 1975.

Nationwide, there are approximately 74,000 community water systems that must meet arsenic standards, with about 4,000 of them expected to exceed the new standard and install treatment or take other steps to comply.

In Illinois, naturally occurring arsenic is found at levels above 10 ppb in some 54 community water supplies.

U.S. EPA estimates that average annual household water bills may increase by $32 a year as a result of treatment or other costs associated with reducing the arsenic levels below 10 ppb. However, costs are expected to be substantially higher, ranging from $58 to $327, for supplies that serve 3,300 persons, or fewer. Nearly 97 percent of the water systems nationwide affected by the new rule are small systems serving less than 10,000 people. Of the 54 Illinois supplies where arsenic levels exceed 10 ppb, all but seven are rated as "small" and serve fewer than 3,300 users.

Because of the significant financial burden on smaller systems, U.S. EPA announced it will provide up to $20 million over the next two years to research and develop more cost-effective technologies to help small systems meet the 10 ppb standard. It also will provide technical assistance and training to small system operators. Funding may be available to water systems for infrastructure improvements under state drinking water revolving loan funds that are supported by matching federal and state funds.

In announcing the 10 ppb standard, U.S. EPA Administrator Christie Whitman said the reduced standard will "improve the safety of drinking water for millions of Americans, and better protect against the risk of cancer, heart disease and diabetes. "