The U.S. Geological Survey is expected to release in the next few months three reports that should provide a good snapshot of more than 220 contaminants considered possible health threats in representative U.S. drinking water supplies.
The first report is scheduled for release Dec. 5, 2008. It will document the occurrence of about 270 substances in both the surface water supply and treated drinking water for nine representative water systems, each serving anywhere from 3,000 to more than 1 million people. The contaminants being evaluated are primarily synthetic organic chemicals such as pesticides, volatile organic compounds, and ingredients in personal care and household products. Drugs aren't included, since USGS is studying those separately.
The contaminants are largely unregulated in drinking water, and treatment processes usually aren't designed to handle them. Although this analysis should provide insights about source-water contamination and the mitigating effects, if any, of typical treatment processes, it won't provide any information on contamination that occurs in the distribution system after treatment.
USGS officials say the system operators are eagerly cooperating so they can find out what's coming into and getting through their plants.
Over the course of the next four years or so, USGS is expected to release, in a couple of phases, its findings for about 20 other similar systems.
The second report will be on a companion study that is looking at nearly identical factors, but for well water supplies, instead of surface water. This study covers 25-30 systems of similar size, with almost no overlap with the surface water systems. The first phase is expected to be released this spring. As with the surface water studies, reports on the remaining well water systems will be released over the next four years or so.
For a brief overview of both the surface and well water studies, see:
- National Water-Quality Assessment Program; Source Water-Quality Assessments,  August 2007.
On the map that is included in this document, you can begin to get an idea of where about half the surface and well water systems that eventually will be analyzed are located. Those expected to be included in the report released December 5 include systems in the Washington, DC, area; western MA; east-central NC; west-central GA; south-central IN; northeastern TX; north-central CO; west-central NV; and northwestern OR.
The third report, expected to be released in late February or early March 2009, will focus on about 220 contaminants, nutrients, and trace elements in more than 2,000 representative domestic wells in 48 states. Each of the wells serves a small number of customers. The contaminants include various chemicals, metals, radioactive substances, microbials, and mixtures of some or all of these. This will be much more comprehensive, both geographically and for substances covered, than smaller USGS studies released in the past couple of years (such as the 2007 report here ). More information on the current study. 
Since all three of the types of water systems studied are supposed to be representative of those around the country, the utilities that serve your audience, and individual well owners, may be spurred to investigate their own situation, as happened earlier in 2008 when numerous drugs were found in dozens of water systems around the country:
- "Drugs in the Drinking Water: States Weigh Whether to Act,"  National Conference of State Legislatures, April 14, 2008.
- "Illinois EPA to assess presence of pharmaceuticals in water supplies and to promote disposal alternatives,"  State of Illinois, March 12, 2008.
- About 50 related stories can be found in the archives of Environmental Health News. 
For fallout from the upcoming USGS studies, check with local utilities, or your state or county health, environment, or public works departments in the case of wells, to identify potential contacts and get their response. Another information source could be the many companies that provide water testing services. Typically, you can find these in the Yellow Pages or in lists from state certifying agencies.