A California state judge tentatively upheld most of the local requirements for stormwater testing that drew a legal challenge from in a write-up issued before a Wednesday hearing.

The Regional Water Quality Control Board in Los Angeles largely has authority to implement the new tests for toxic chemicals, Judge Stephen Goorvitch of California Superior Court, Los Angeles County said in a tentative ruling.

But he may narrowly grant part of Boeing's request by asking the board to reconsider a couple portions of the test. Goorvitch flagged that the board needs to submit more specifics on which chemicals certain ...