Our 840 square foot unit is a manufactured home that maximizes the size allowance for a Sonoma County second unit. Little House on the Trailer Modern Exterior

A second unit permit is around $20,000 in Sonoma County.

You will need a property served by a sewer or 2 acres served by a septic tank. There may be a requirement to upgrade the septic system or hookup to a sewer. Septic upgrades may range from $20,000 to $40,000.

Fire sprinklers and adequate pressure to drive the sprinklers will be required and can add from $5000 to or more to the project.

There will be parking requirements for the second unit and any such other requirements particular to your lot.

The permit process for this type of home is described under “How to get a Second Unit Permit” which can be found in the “News” blog tab on this site.