Merced County, CA Building Safety: Fire Sprinkler Requirements (2026)

Merced County's ADU chapter is built to keep accessory units from facing extra hurdles that do not apply to the primary home, and fire sprinklers are one of the standards it addresses directly. 62: the unit is deemed an accessory use and a residential use consistent with the General Plan or zoning designation, it is not considered in applying growth-control ordinances, it does not count toward allowable density, and, under subsection E, it shall not be required to provide fire sprinklers if they are not required for the primary residence.

In practice, that means the county does not layer an independent sprinkler mandate onto ADU construction; the applicable California Building Code and California Residential Code sprinkler triggers for the primary dwelling on the parcel control whether the ADU needs sprinklers too. If the primary residence is not required to have fire sprinklers, for example because it falls under a code exemption for existing one- and two-family dwellings, the new ADU built on that same lot is not required to have them either. The same subsection also spares ADUs and JADUs from other add-on requirements: they are not required to provide a passageway (subsection F), are not treated as a new residential use for utility connection or capacity charges unless built alongside a new single-family dwelling (subsection G), and are not required, as a condition of ministerial approval, to correct pre-existing nonconforming zoning conditions on the parcel (subsection H). 050.