Mountain View Companion Unit

This is the term used by the City to describe ADUs. A companion unit is a second living unit located on the same lot as a single-family home in the R1 (Single-Family) Zoning district. They are also referred to as “granny units” or “in-law units.” Companion units typically contain a bathroom, one or two bedrooms, a kitchen and, sometimes, a garage or carport. Companion units provide housing opportunities within single-family neighborhoods and are either attached to or separated from the main home.

A Summary of the regulations is available here.

The City has approved a new set of regulations, see “City’s New Companion Unit Regulations”

There is no minimum lot size to build an ADU. Allowed size depends the lot size, but can be between 150 and 700 sq.ft.  Mountain View allows attached, detached and over an existing garage for its ADUs.

Mountain View Planning Department

Mountain View Building & Fire Inspection