Mountain View ADU Standards

Prefab ADU in Mountain View

What is an Accessory Dwelling Unit (ADU)?

An ADU is an independent residential unit on the same lot as a primary home, providing additional living space, rental opportunities, or multi-generational housing. A prefab ADU is a permanent, factory-built backyard home that meets local zoning and building codes, making it ideal for long-term living.

Tiny homes, often confused with prefab ADUs, are small, mobile units built on wheels. While both can be considered ADUs, prefab ADUs are stationary and built to last, whereas tiny homes face more zoning challenges due to their mobility.

Planning to Build an ADU in Mountain View?

With the implementation of ADU regulations, Mountain View has seen a rise in accessory dwelling unit construction. If you’re planning to build an ADU in Mountain View, LiveLarge is here to guide you through key development requirements for a smooth and successful project.

Types of ADUs

  • Detached: A newly constructed unit separate from the primary structure.
  • Attached: A newly constructed unit attached to the primary structure.
  • Conversion: A conversion of existing space within a primary residence or a detached accessory structure.
  • Junior Accessory Dwelling Unit (JADU): A conversion of existing space, up to 500 square feet, contained entirely within a single-family residence.

Zoning and Lot Size

Accessory dwelling units and/or junior accessory dwelling units are permitted on a residential site as follows:

  • Single-Family Lots:
    • One (1) ADU and one (1) JADU per lot with a proposed or existing single-family dwelling, subject to Government Code Section 65852.2(A).
    • One (1) detached ADU (new construction) with a minimum four-foot side and rear-yard setbacks for lots with a proposed or existing single-family dwelling. A JADU may be combined with this ADU.
  • Multi-Family Lots:
    • Multiple ADUs are allowed within portions of existing multi-family dwelling structures that are not used as livable space (e.g., storage rooms, boiler rooms, passageways, attics, basements, or garages) if each unit complies with Chapter 8 of the city code.
    • At least one (1) ADU is allowed within an existing multi-family dwelling, and up to 25% of the existing multi-family dwelling units may be converted into ADUs.
    • No more than two (2) detached ADUs are allowed on lots with an existing multi-family dwelling, subject to a height limit per Section 36.12.85 and a four-foot rear and side setback requirement.

Size and Floor Area

  • Attached ADU
    • 0–1 Bedroom: Maximum area of 850 sq. ft.
    • 2 Bedrooms: Maximum area of 1,000 sq. ft.
    • Shall not exceed 50% of the primary residence’s floor area.
  • Detached ADU
    • 0–1 Bedroom: Maximum area of 850 sq. ft.
    • 2 Bedrooms: Maximum area of 1,000 sq. ft.
  • Junior ADU (JADU)
    • Maximum area of 500 sq. ft.

Setbacks & Height

  • Attached ADU
    • Setbacks: 4-foot side/rear setbacks
    • Height: 28 feet
  • Detached ADU
    • Setbacks: 4-foot side/rear setbacks, 6 feet from the primary residence, front setback per the underlying zone
    • Height: 28 feet
  • Conversion of Existing Area
    • Setbacks: No setbacks are required for the conversion of an existing living area or accessory structure or for a structure rebuilt in the same location and to the same dimensions as the original.
  • Junior ADU (JADU)
    • Setbacks: 4-foot side/rear setbacks

Parking Requirements

  • One (1) space (covered or uncovered), which may be provided in a garage, carport, or as tandem parking in a driveway.
  • No parking space is required if any of the following conditions are met:
    • The unit is located within ½ mile walking distance of public transit.
    • The unit is within an architecturally or historically significant district.
    • The unit is part of the existing primary dwelling unit or an existing accessory structure.
    • On-street parking permits are required but not offered to the occupant of the ADU.
    • A car-share parking space is located within one (1) block of the ADU.
    • When an existing garage, carport, or covered parking structure is demolished or converted into an ADU, no replacement parking spaces are required.

For more information, contact the Mountain View Planning Division at (650) 903-6306 or via email at planning.division@mountainview.gov.

Why Choose LiveLarge Prefab ADUs?

LiveLarge prefab ADUs are designed to meet Mountain View’s detached ADU regulations, offering a hassle-free way to maximize property value. With pre-approved designs and expert guidance, we ensure a smooth approval process.

Let LiveLarge be your trusted partner in your ADU journey. With our expertise in design, construction, and pre-approved plans, we ensure your project aligns with local standards and maximizes your property’s potential. Contact us today to start your ADU project!

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