The U.S. Environmental Protection Agency finalized the much anticipated arsenic standard that reduces the maximum contaminant level (MCL) from the current 50 parts per billion (ppb) to 10 ppb.
The Safe Drinking Water Act, as amended in 1996, requires EPA to revise the existing drinking water standard for arsenic.
The EPA considered costs, health concerns and specific data including data for 3 and 20 ppb that would also have ensured higher quality public water free of arsenic.
According to the Association of California Water Agencies, reducing the MCL to 5 ppb would require $1.7 billion in capital costs and annual costs of $220 million. Also in the report were capital cost figures for $500 million for a 10 ppb standard and $260 million for a 20 ppb standard.