An accessory dwelling unit (ADU), also referred to as a companion unit, in-law unit or granny flat, is a dwelling unit that provides complete, independent living facilities on the same lot as a single-family or multi-family dwelling. Independent living facilities includes permanent provisions for living, sleeping, eating, cooking and sanitation (restroom/wash facilities). These units can be detached from an existing dwelling or attached to an existing dwelling. For more information and current regulations for ADUs and Junior ADUs (JADUs), visit the ADU webpage.

Permits

ADUs and JADUs do not require a Planning permit, but do require a building permit. Planning staff encourages a property owner, or architect, to have their proposed plans preliminarily reviewed by a Planner prior to submitting for building permits. This is to ensure the ADU and/or JADU complies with the development standards and that plans include all necessary information.

No appointments or fees are required for informal review, as they are completed on a first-come, first-serve basis at the public counter or by email at planning.division@mountainview.gov.

An accessory structure is considered any secondary structure or equipment located on a property, including (but not limited to) the following:

• Detached garage;
• Detached structure (i.e. studio, shed, etc.);
• Trellis, arbor or gazebo;
• Spa, pool;
• BBQ, outdoor kitchen, chimney, fire pit; and
• Any other structure in the side or rear yard.

Development Standards

Like your home, an accessory structure has specific development standards regarding setbacks from property lines, size limitations, separation requirements between structures, height limitations, etc. Unless otherwise identified, all accessory structures count towards the permitted floor area allowed on a given property.

Accessory structures may be conditioned (heated) living space and may include a full bathroom (up to 3 plumbing fixtures and a water heater), if desired, but are not permitted to have a kitchen or be rented out as a living unit. Once a structure is deemed habitable or conditioned space, fire sprinklers are required.

Permits

Any accessory structure over 120 sq. ft. in size, measured at the foundation, with or without electricity, plumbing and/or mechanical (heating/cool) equipment requires building permits. Structures and sheds which are 120 sq. ft. or less in size without any utilities do not require a building permit, but are still required to comply with accessory structure development standards. Any structure closer than 5 feet to the property line may be required to meet fire rating requirements.

For questions on building and fire requirements, please contact the Building Division at 650-903-6313 or building@mountainview.gov.

Trees and Landscaping

Most trees located at a single-family home are private trees, which are not regulated by the City. However, there are two types of trees – Heritage Trees and Street Trees – which are regulated by the City and require permits by the City of Mountain View’s Forestry Division. For more information, visit the Trees and Landscaping page.

No permits are required for installation of new or modified landscaping at a single-family home in the R1, R2 or R3 zoning districts, unless a Planning permit is required for other aspects of development and 1,000 sq. ft. or more of new or modified landscaping is being installed. Additional information regarding landscaping is available on our Trees and Landscaping page.

Fences

Fence regulations are important as they ensure consistency within a residential neighborhood and safety for drivers, pedestrians and bicyclists. All fence regulations for single-family homes are available on our Fences page.

Neighbor Challenges

Though we encourage neighbors to have open communication and resolve conflicts peacefully and thoughtfully, we understand that sometimes help from a third party is needed. The Mountain View Mediation Services is a free and confidential program provided by Project Sentinel to assist residents in disputes.

Mountain View Mediation Services can be reached by phone at 650-960-0495 or by email at mediate4mv@housing.org.

Placement of Pods or Other Storage Units on the Roadway

The City of Mountain View does not allow the placement of PODS or other storage units on the public roadway as they do not meet Section 670 of the California Vehicle Code. Placement of units in the public right of way may result in a citation and fines.

Requirements

The parking requirement for a single-family home is, at minimum, one (1) covered parking space and one (1) uncovered parking space. A parking space is identified as a 9 feet wide by 20 feet deep unobstructed space with a height clearance of 7 1/2 feet for vehicle storage. The unobstructed space cannot contain any equipment (i.e. washer/dryer, water heater), storage or have a door open within it.

Covered Parking

The covered parking space can include either a carport or a garage. If the covered parking is attached to the house, then it must comply with the development standards of the house. If it is detached from the house, as a separate structure, then it must comply with the accessory structure development standards.

Uncovered Parking

The uncovered parking space can be located in either a driveway or dedicated pad for vehicle parking and can be located within the front setback. Allowable driveway materials include paving, asphalt, tire-track paving, and gravel cups. No loose sand, rock or granite filings are allowed as they clog the City's storm drain system.

Street Parking

Most streets accessing single-family homes are public streets, owned and maintained by the City. As such, street parking on a public street is permitted and cannot be regulated by adjacent private property owners. If a suspicious car is parked for an extended period of time, 72 hours or more, or someone is blocking access to your driveway, please contact the Police Department’s non-emergency phone line at 650-903-6395.

Informal/Preliminary Review

City staff encourages all property owners and architects to share preliminary/informal plans of any addition or new construction with Planning and Public Works staff prior to drafting plans for building permit review.

Initial review by a Planner and Public Works Engineer can save time and money, as city staff will verify the proposed work complies with the required development standards and ensure the proper information is included on the plans. This informal review is free of charge and can typically be done in a single visit to City Hall, though may take additional time if a property has a unique feature that requires additional staff review. No appointment is required, as your plans will be reviewed on a first-come, first-serve basis at the counter.

Planning Permit

The City of Mountain View does not have discretionary design review for single-family home development nor requires noticing of adjacent neighbors of construction activity, as an effort to reduce costs, time and process for homeowners. As long as a remodel, addition or new construction of a home complies with the development standards of the zoning district in which the property is located, then no permit is required by the Planning Division, except for the cases listed below. Development standards include required setbacks from the property lines, height restrictions, floor area restrictions, minimum yard requirements, etc.

Permits are required by the Planning Division in the following cases:

• An exception to the development standards, including variances and floor area ratio exceptions;
• A conforming addition to a nonconforming home;
• An addition or new construction of a home with a lot of 10,000 sq. ft. or more located adjacent to a creek;
• Any exterior changes or additions to a historic home; and
• New subdivision of 5 or more homes.

More information on Planning application materials and permit fees is available on our Forms & Fees page.

Building Permits

Building permits are required for most construction activities to confirm the work being completed is built to the current California Building and Fire Codes and City standards. Permits are not required for some minor repairs or modifications, such as repairing dry wall, painting and carpeting. However, permits are required for work that involves installing/replacing equipment and upgrading or replacing structural or building components of the home, such as, but not limited to, reroofing, replacing a porch, installing an AC unit, replacing a water heater, installing new windows, etc.

Confirm if a building permit is needed for your project at 650-903-6313 or building@mountainview.gov.

Specific information and materials are required to be submitted to the Building Division for building permit review, visit the Building Division webpage for more information.

Construction Thresholds

Construction thresholds for additions, remodels and new construction, which may add additional cost or scope to your proposed project include:

• For a new single-family home or any addition of 500 or more habitable sq. ft. to an existing single-family home may be subject to school impact fees. Properties are given credit for existing legally-constructed building square footage.
• Any addition, or equivalent remodel, of 600 sq. ft. is subject to Public Works review, where one or more of the following improvements may be required (some of which may require a sidewalk or excavation permit if located in the public right-of-way):
  
  • Inspection and replacement of the sanitary sewer lateral;
  • Replacement of the driveway apron to meet accessibility requirements;
  • Reconstruction of a portion of sidewalk, if there are major cracks or breaks;
  • Upsizing the water service and meter, if a fire sprinkler system is installed.
    Any addition of 1,000 sq. ft. or more must comply with the Mountain View Green Building Code.
• Any new living unit (new construction of a single-family home) may be subject to the Park Land fee collected by the Public Works Department. To determine if your new construction project is subject to the fee and for an estimate, contact the Public Works Department at 650-903-6311 or public.works@mountainview.gov.
• A residential fire sprinkler system is required with: (1) any new construction home, (2) any addition that results in a total size of 4,100 sq. ft. (new + existing sq. ft.), and (3) any addition which doubles the size of an existing home.
• Any new addition or remodeling of an existing home built pre-1978, where children or pregnant women reside during construction, must comply with the US EPA regulations for prevention of lead poisoning.

Property Line Locations

The City does not maintain records of the physical location of your property boundaries. To determine the exact location of your property lines, you will need to hire a land surveyor (civil engineer). Fences are not typically located on a property boundary, so they should not be used as an accurate reference of where your property line is located.

A land survey is not required to submit for a planning or building permit, but may be required during construction should questions or concerns arise about the property boundaries.

Easements

Some single-family properties have an easement on-site. Easements could allow access to utility lines and waterways located on or nearby the property or ones that grant pedestrian access along or through the property.

Utility easements are the most common for single-family properties and are often for PG&E or the Santa Clara County Water District to operate and maintain utilities or access to a creek. A description of the easement boundaries is located in the legal description of your property, as part of the Title Report or Grant Deed. A property owner should be aware of any and all easements located on their property as it may restrict permitted development, since no structures can be built within an easement area. The city does not keep records of easements on private property.

For further questions regarding easements, please contact the Public Works Department at (650) 903-6311.

Tax Assesor Maps

The City utilizes the Santa Clara County Tax Assessor Maps (SCCTA) as a general reference, which provides basic information about your lot dimensions (width and depth) and existing building square footage. The Assessor map and data are good starting points to identify basic information about your property and are available online at the SCCTA website.

Zoning Districts

Every property within the City is located within a specific zoning district, which identifies allowable land uses and establishes development standards for all properties. Most single-family residential homes are located in the R1 (Single-Family Residential) district. However, a portion of single-family homes are located in other residential districts, including the R2 (One- and Two-Family Residential) district and the R3 (Multiple-Family Residential) district. Knowing which zoning district your property is located is important as it will identify the specific development regulations applicable to your property.

To identify the zoning for your property, please visit our interactive zoning map where you can search by address.

Development Standards

View more information on zoning, including a Zoning Map and development standards for zoning districts.

Flood Zones

Some residential properties in Mountain View are located within flood zones, known as Special Flood Hazard Zones. The Federal Emergency Management Agency (FEMA) identifies and manages flood zones throughout the US. While construction is permitted in these zones, there are special construction requirements and standards when substantial improvements are being made to the home, including new construction, remodels or additions.

To determine if your property is within one of these zones visit the City's flood zone website or contact the Public Works Department at (650) 903-6311 or public.works@mountainview.gov.

All flood zone maps are available online at FEMA’s Map Service Center.