Legal Question in Construction Law in California

Re: Storm Water and Silt Discharge

You are partly right.

The law on storm runoff in California has its roots in the old Civil law, reflecting our Spanish/Mexican heritage as opposed to much of our law which derives from English common law.

Under the old law, water flowing according to nature could not be the basis for a suit. On the other hand, anyone who tinkered with nature in the slightest was strictly responsible for the consequences.

In 1968 the California Supreme Court changed the Civil Law rule somewhat, to adapt it to the realities of a modern, increasingly crowded and developed state. As modified, uphill landowners no longer have an absolute duty nor an absolute liability. A rule of reason is now applied. An uphill owner can modify (grade, pave, develop) so long as he does so reasonably. He is liable for unreasonable impacts upon his downhill neighbor.

The case is Keys versus Romley (1968), reported at 64 Cal.2nd 396. You can read it at your county law library, or perhaps on line. Try FindLaw.com.

There would also be local ordinances regarding grading permits, etc. If excavations are involved, see Civil Code section 832.