In another of The New York Times’ startling articles on the state of U.S. waters, Charles Duhigg reports on the myriad chemicals polluting drinking water supplies and regulators’ inability to manage them.

The whole article is worth reading for its insights into public health, public policy, and even public relations. On the regulatory front, it seems like it boils down to essentially two problems.

First, for contaminants for which drinking water standards do exist, the standards are too high. “For instance, the drinking water standard for arsenic, a naturally occurring chemical used in semiconductor manufacturing and treated wood, is at a level where a community could drink perfectly legal water, and roughly one in every 600 residents would likely develop bladder cancer over their lifetimes, according to studies commissioned by the E.P.A. and analyzed by The Times.”

Second, too many contaminants are completely unregulated – and the more time that passes without regulation, the longer the queue grows, as new chemicals enter into commerce.

The Times article examines the Safe Water Drinking Act and EPA’s enforcement of it. A major component of EPA’s implementation of the Act is the contaminant candidate list, a catalog of chemicals “that are currently not subject to any proposed or promulgated national primary drinking water regulations, that are known or anticipated to occur in public water systems, and which may require regulation,” according to the EPA. The list is to be updated every 5 years.

The good news is that In October EPA updated the list which now includes 116 contaminants, up from 51 in 2005, according to EPA’s website. (The ’05 update was late.) Recognizing the growing concern over hormone-imitating compounds in the water supply, EPA added to the final candidate list nine hormones that weren’t on an earlier draft list, according to BNA news service (subscription).

The bad news is that EPA never follows through. In July 2003 and again in July 2008, EPA announced its final determination that no regulation was necessary for contaminants on the list. The next round of determinations – or lack thereof – is due by 2013.