The State of California Housing and Community Development (HCD) has jurisdiction over the manufacture and alterations of all manufactured/mobile homes in California. All electrical, mechanical, plumbing, and structural alterations associated within such a unit requires a permit.
HCD has a matrix that shows what work can be performed without a permit and what operations require a permit. View HCD matrix.
The City of San Marcos does not regulate work to the mobile home unit and permits are not required by the City.
Building permits are required from the City for all work done outside the unit including initial set-downs, porches, awnings, carports, sheds, lot service alterations, and cabanas (room additions). Simply complete the application and submit along with two (2) sets of plans for the proposed project. The application includes park management approval.