Accessory Dwelling Units

Dear Residents,

While State law again has made a blanket law allowing ADUs in municipalities without review or study as to the cumulative impacts to a neighborhood/town/city, we should be cautious as to impacts to safety within a neighborhood, parking space availability in neighborhoods, short term rentals, use of the owner for their own needs and not to provide housing supply.

I do want to point out that the majority on Council went beyond what State law mandated without any consideration to the negative cumulative impacts to the entire city, especially to the character, safety and sanctity of neighborhoods.  Parking is already a major issue, with our many narrow neighborhood streets. The passing of this ordinance will further impact the safe use of Palo Alto’s Complete and Safe Routes to School program.

Many concerned citizens mentioned that these new policies promoting growth will be a cause for neighbor with neighbor disputes. We have in the past experienced this with trees, now it can be parking, or noise, or loss of privacy, etc. Yet Mayor Scharff, Vice-Mayor Kniss, Council Members Wolbach, Fine and Tanaka pushed this ordinance through without further impact analysis or moving forward cautiously using Staff’s March 7th recommendation.  The Mayor’s message in the news media mentions that there was a “compromise". If you consider limiting lot size in order to build an ADU to 5000 sf and reorienting the ADU front door to the side or back of the property as "compromises", you are not acknowledging the larger and long term unintended consequences that neighborhoods will have to bear. Before you know it, permit parking, more infrastructure-based fees, school enrollment impacts, parks and open space impacts, etc. will be imposed upon you.

Of particular concern are the already heavily impacted areas in which newly built ADUs and JADUs are allowed and parking is exempt. The following diagrams from the Staff proposal followed State mandated parking regulations within 0.5 or 0.75 miles from public transportation as show in the diagrams. 

Red circles show area within 0.75 miles of a Caltrain. Green circles show area within 0.50 miles of public transit.


The following chart shows:

  1. Current ordinance,
  2. State Law,
  3. Staff proposed changes in the Staff Report on March 7th,
  4. Expanded version passed by the Council on March 7th and
  5. Proposed ordinance passed on April 17th. (A second reading on the Consent Calendar at least 10 days later will be required for adoption.)


Development Standards

Current Ordinance (R-1 Standards)*

State Law Restrictions
January 1, 2017

Staff Proposal 
March 7th

ADU Ordinance 
March 7th

New ADU Ordinance 
April 17th


  • Side: 6-ft


  • Back: 20-ft


  • 12 feet separation buffer between existing single family home and detached ADU.

Not stated, Local government may establish for detached ADUs

  • No setbacks required for existing garage converted to an ADU but only apply if existing garage is not needed as required parking for principal dwelling.

  • Permits construction of an above garage ADU with a maximum side and rear property setback of 5ft.

No Change from current City ordinance; and

  • ADUs shall comply with the underlying zoning district’s setbacks
  • Eliminate current code’s 12 feet separation buffer between existing single family home and detached ADU
  •   Require no more than 6-ft side and rear setbacks for ADUs
  • Require no more than 6-ft side and rear setbacks for ADUs


  • 2 parking spaces, /1 covered

  • Cannot be in front setback
  • Not to exceed 1 per unit or per bedroom
  • May be located in setbacks or tandem, unless special findings
  • No parking required:
    • if ADU is within half mile from public transit
    • Is within an architecturally and historically significant historic district
    • Is part of an existing primary residence or an existing accessory structure.
    • Is in an area where on-street parking permits are required, but not offered to the occupant of the ADU.
    • Is located within one block of a car share area.

Same as State law; and

  • ADU is within 0.75 miles of a Caltrain station or 0.5 miles of public transit with fixed route bus stops with service intervals of 15 minutes or better during peak commute hours.
  •  No parking required for ADUs    Parking already exempts for JADUs
  •  If an ADU will occupy the existing parking for the primary residence (i.e., garage conversion
    to ADU), replacement required parking would be able to be provided on an existing driveway
    within the front setback.
  •  No Parking required for ADU or JADU, even previously approved ADUs will not be required to retain parking spaces that were previously required.
  • Remove requirements for covered parking on properties with an ADU or JADU
  • If an ADU will occupy the existing parking for the primary residence (i.e., garage conversion
    to ADU), replacement required parking would be able to be provided on an existing driveway
    within the front setback.

Minimum lot size /  Lot Coverage

  • 35% greater than minimum lot size for R-1 lots

Local government may establish minimum and maximum unit sizes

No Change from current City ordinance

  • Permits ADUs, regardless of lot size, on all residential districts, except the RM-15, RM-30, RM-40 and OS districts.
  • Remove Lot Coverage requirements for ADUs
  •  ADUs should be limited to lot sizes of 5,000sf or more. JADUs are exempt from this requirement.
  • Allow 2-story ADUs in the RE (Residential Estate - usually lots that are larger <20,000sf) zones with existing setbacks.



ADU Height

  • R-1 zones have height restriction of 17th for both attached and detached ADUS and 1-story.

 Not stated, local government may establish

  • R-1 zones have height restriction of 17ft for both attached and detached ADUs and 1-story.
  •  Limit ADUs to 17-ft high and single-story including SSO neighborhoods, even if the main house is a grandfathered 2-story house.
  • In RE zones. -In RE zones, ADUs may be 2-stories and 30-ft.
  • In OS zones, attached ADUs may be 2-stories and 25-ft.

No change from March 7th; and

  • Direct Staff to return with potential Eichler design guidelines relating to ADUs, including lower height limits.

Smoke Detectors / Carbon Monoxide Detectors

Federal and State Law apply.

No fire sprinklers shall not be required if they are not required in the primary residence.

Federal and State Law – Smoke and Carbon Monoxide Detectors

Federal and State Law apply.

Federal and State Law apply.



All impact fees, including water, sewer, park and traffic fees must be charged in accordance with the Fee Mitigation Act,

  • Building permits would be required for new ADUs and JADUs and associated building permit fees would be collected for the review/permitting process.
  • No fees collected for hook-up fees for JADUs.
  • Limit on the collection of fees for ADUs.



Other Give-Aways


  • Ministerial approval of ADUs if unit complies with certain parking requirements, the maximum allowable size of attached ADU and setback requirements.
  • The single-family residence in which the JADU is created or JADU must be occupied by the owner of the residence
  • The owner must record a deed restriction stating that the JADU cannot be sold separately from the single family residence and restricting the JADU to the size limitations and other requirements of the JADU ordinance.
  • For ADUs that require an addition or a new accessory structure, development standards such as parking, height, lot coverage, lot size and maximum unit size can be established with certain limitations.
  •  Require that either ADU or single family home be owner occupied.
  • Property owner must reside in the primary unit or ADU. This new requirement would enable Code Enforcement staff to respond to concerns about absentee owners and property maintenance.
  • Prior to issuance of a building permit for the accessory dwelling unit, the owner shall record a deed restriction in a form approved by the city to notify future owners of the owner occupancy requirements and restrictions on short-term rentals.
  • 30-day minimum rental.
  • ADU architectural design and compatibility requirements are removed.
  • Ordinance to allow a property owner to rent both the ADU and principal residence to one tenant without screening.
No change from March 7th; and
  • Reinstated language pertaining to doorway orientation.


For more information, check out Doug Moran’s blog 

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  • Lydia Kou
    published this page in Home 2018-03-03 16:57:32 -0800