The County has  adopted the San Martin Integrated Design Plan in 1995, which contains design guidelines for non-residential uses, drainage issues, circulation issues, and rural residential subdivision and cluster subdivision issues.

The design guidelines in this design plan are intended to inform and guide the public and private property development in San Martin so that the form and character of the overall community is protected and enhanced

For the complete document see here

https://www.sccgov.org/sites/dpd/DocsForms/Documents/SanMartin_DesignGuidelines.pdf