Years of runoff, pesticides, air and ground pollution are overdue for analysis, according the EPA and The Sacramento Bee.
Addressing the accumulating problems is long overdue, so the Environmental Protection Agency is using the Clean Water Act of 1948 to do a comprehensive analysis.
The watershed, home to millions of people and a large agri-business sector, is the size of Florida. The delta itself drains half of California's precipitation and is the largest on the West Coast.
Jared Blumenthal told the Bee: "This is an incredibly critical ecosystem that is on the brink of collapse. This, for the first time, tries to look holistically and say, 'What should be done that isn't being done, and are there things EPA should do that we're not.' "
While pesticides from farming leap to mind, household cleaners and "what's under your sink" are a proven major contributor to the Delta's downslide.
The EPA will collect public information for the next two months.
