Frequent Questions

Under the Safe Drinking Water Act (SDWA), has the action level for lead always been 15 ppb?

Initially, under the National Interim Primary Drinking Water Regulations, lead was regulated by an MCL of 0.05 mg/L. The MCL was derived from the 1962 Public Health Service Act standard, a later revision of the 1941 standard (40 FR 59566; December 24, 1975). This level was based on the estimation that this level of lead in drinking water would contribute about a quarter to a third of the lead normally ingested by a child and about a third of that in food for an adult (50 FR 46936, 46971; November 13, 1985).
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