The EPA is recommending priority improvements on 121 water supplies, which provide water to 940 thousand people.
It's a slight drop on the number of supplies earmarked for essential improvements at the beginning of last year.
Over 99 percent of supplies comply with microbiological and chemical limits, according to the EPA's Drinking Water Report for 2013 released today.
But over 20 thousand people, on 20 public water supplies, are affected by boil notices.
