As part of supplying drinking water, a public water supply system must test its water for the contaminants regulated under the Safe Drinking Water Act;
(a public water supply system; must test; its water for the contaminants) (the contaminants; regulated; L:under the Safe Drinking Water Act)
a public water supply system the contaminants
must test regulated
its water for the contaminants
L:under the Safe Drinking Water Act