In the desert Southwest, there's a lot of talk and concern about water, mostly in terms of supply and conservation. However, water quality is as important as quantity, especially in terms of personal health.
The Environmental Working Group has developed a Drinking Water Database with information about tap water quality for different locations. They also have a handy PDF printout for safe drinking water as well as a guide for buying water filters. One drawback is that this advocacy group relies on reporting from government agencies for its data. For example, the analysis for the City of Santa Fe's water supply is from testing done in 2004-2006. This is the data the New York Times used in a profile last month, and also what the Santa Fe Reporter posted on its blog.
However, the City of Santa Fe has water quality data from 2008 (PDF). They post annual reports, so it's safe to assume that we'll be getting the 2009 data shortly as well. The annual reports include a table that isn't as detailed as the high-profile older one, but the more recent data is heartening. Arsenic levels, for example, were under the legal limit in 2008, which is an improvement from the 2004-2006 data. The USGS also posts up-to-date water quality data for all of New Mexico. Real-time data is available from sites in the Rio Grande and Pecos River basins.
If you'd like to educate yourself more about the myriad issues surrounding water quality and quantity, we have plenty of books for all ages, especially in the Environmental Education Resource Center. We also have links to various Drought & Water websites that should help answer any questions you have.