Permit & Code Info for Tiny House Lovers in Marin County

I just did a quick round up of links to basic permit and code information for the county of Marin, in Northern California. It also works as a search pattern for tracking down this info quickly on the internet for almost any location. Seems a shame to not share it in case it might be useful to someone, so here it goes:

In Sonoma County we start by finding out the zoning of the particular parcel. We head to the Permit and Resource Management Department online and look up the address. In Marin using similar search terms I found the Marin Assessor-Recorder page. Enter a parcel number from tax records and get the zoning codes and tax status on this page. If you don't know the parcel number you can look it up at the Assessor's Office using this mapbook index. This tells you which mapbook the property is in, and then you go to the County Assessor's Office and look up the parcel in the appropriate mapbook. Use the parcel number to track down the zoning. You need to know the exact zoning because sometimes a special zoning lets you do more on a parcel, and other times habitat or natural features puts a parcel in a special sub-zoning that may be more restrictive. Once you find out the exact zoning for your parcel look up the zoning laws that govern it and see if there's anything especially restrictive you need to be concerned about. Here's the municode, aka Marin County Code, with a zoning section that covers all the pertinent information.

Marin County also has a general information sheet on codes in which I found this exemption for buildings less than 120 square feet used as accessory (non-habitable) buildings. However note that installing any electrical or plumbing service to such structures still requires a permit, which could be a problem if you're trying to get a plumbing inspection on a bathroom in a "shed". Generally as soon as a bathroom is involved that makes it habitable and then it's not allowed. One strategy is to build the exterior shell without any interior walls or finish, put in the electrical and plumb it with a sink - because you need to wash your hands and water plants in your potting shed, right? - then get your permits and inspections. After all the officials are gone you can install interior walls, insulation, toilet, etc. You still have a building that would not be considered legal if officially inspected, but you can be quasi-legal up to the moment you put in a bathroom and still get the assurance of knowing the electrical and plumbing systems were considered safe and legal by code standards

WORK EXEMPT FROM A PERMIT
Exemptions from permit requirements do not grant authorization for any work to be done in any manner in violation of the provisions of any laws or ordinances of the County of Marin. Please contact Planning, Environmental Health Services and Land Development Divisions prior to commencing any building permit exempt work.
A Building Permit shall not be required for the following (CBC Appendix Ch.1 Section 105.2):
1. The following types of structures may be exempt from a building permit if they are located in compliance with zoning regulations established in MCC, Title 22.
Please contact the Marin County Planning Division at 499-6269 for specific requirements for your property.
A. One-story detached accessory buildings used as tool and storage sheds, playhouses and similar non-habitable uses, provided the total gross area does not exceed 120 square feet. MCC 19.04.060
(deleted a lot of irrelevant exempt items like oil derricks(!) and fences not more than 6' tall)
B. In rural areas on parcels of 1 acre or more, accessory structures used for tool sheds, workshops and horse stalls not exceeding 300 square feet each and fences over 6 feet in height may have permits waived if exempt from zoning regulations.
Separate plumbing, electrical and mechanical permits will be required for related work in conjunction with the above exempted items.