CA Gov't Code Section 66474.8

No ordinance, regulation, policy, or procedure which regulates or prescribes standards for grading or drainage, adopted by or applicable to a local agency pursuant to Section 17922 or 17958 of the Health and Safety Code, shall apply to the construction of design or improvement work, including the rough grading of lots within the subdivision, performed pursuant to, or in connection with an approved or conditionally approved tentative map, final map, or parcel map unless the local agency has no other applicable ordinance, regulation, policy, or procedure which regulates or prescribes standards for grading or drainage for subdivision design or improvement.