A ban on drinking tap water remains in effect indefinitely for nearly 5,000 Paradise Valley and Scottsdale customers of Arizona American Water while the company works with government health officials to test water samples for a potentially toxic solvent.
The ban, which began Wednesday, urges customers not to drink tap water or use it to prepare food.
Arizona American's initial warning was to expire at 5 p.m. Friday but now is indefinite.
After the problem was detected, a test of the water showed the level to be 22 parts per billion. 5 ppb is the maximum contaminant level allowed.
Thursday, it had dropped to 1.9 ppb, within acceptable levels, but more checks of the system are needed.
Read the complete article (linked above) for more details, but to summarize - the affected customers in Scottsdale and Paradise Valley still shouldn't use their tap water for drinking or food preparation.
Arizona American Water's latest (18 January 2008) press release is here.
Arizona state government FAQ page on this is here.
Edit to add:
There is a blog, The TCE Blog, that is dedicated to publicizing the effects of TCE. If you are interested in learning more about TCE, it's worth a read. It's written by Neil Fischbein, who once lived in a town with a water supply that was contaminated with TCE.