The Marin Post

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Misguided Housing Bill Bans Single-Family Zoning Forever

A fundamentally flawed housing bill, Senate Bill 9 (Atkins) is fast-tracking through the State legislature. SB-9 is a reiteration of Senate Bill 1120 from last year. Like its predecessor, the bill is an unprecedented taking of local planning powers that hands county, city and community decision-making directly to market-rate and luxury housing developers. Worse still, the bill could ruin treasured single-family neighborhoods.

SB-9 ends single-family zoning and requires jurisdictions to “ministerially” permit an urban lot split and/or a duplex on single-family parcels, as long as the subject parcels and developments meet specified conditions.

“Ministerial” approval streamlines the permit process and eliminates discretionary review, environmental review in compliance with the California Environmental Quality Act (CEQA), and public hearings, thereby stifling public engagement, democracy, high-quality development, and environmental protections.

The bill would let developers buy up single-family parcels as small as 2,400 sq. ft., subdivide each parcel into two 1,200 sq. ft. lots and then build duplexes on each lot. The result would be four homes, where there used to be only one.

When combined with the State Accessory Dwelling Unit (ADU) law, SB-9 allows for the creation of up to six or eight units, and maybe even 10 units (although this is a stretch) in single-family residential zones.

Under SB-9, a city is not required to approve an Accessory Dwelling Unit (ADU) or a Junior Accessory Dwelling Unit (JADU) where both the lot-split provision and the duplex provision are invoked. Section 6582.2 (e) of SB-9 states; “A local agency shall not be required to permit an accessory dwelling unit on parcels that use both the authority contained within this section (the two residential units per single-family lot section) and the authority contained in Section 66411.7 (the lot-split section).” However, there may be creative ways to get around this stipulation.

Here are the possibilities:

An expert legislative analyst determined that Senate Bill 9 could result in the following development scenarios:

Rear and side setbacks are limited to merely 4 feet. Garages, yards, spaciousness, privacy and views are disregarded.

Also detrimental, SB-9 lowers parking requirements to just one space per home and totally eliminates parking requirements on developments located within one-half mile walking distance of either a "high-quality transit corridor" or a "major transit stop" or if there is a car share vehicle located within one block of the parcel.

Without any affordability requisite, the bill primarily benefits real estate investors, real estate developers, building contractors, and home rental companies. Overlooked are the concerns of homeowners, many of whom spent their life savings to live in a peaceful, scenic single-family neighborhood.

A 2019 Redfin survey found that regardless of where people live within the US, more than 85% of home buyers and sellers (including millennials) prefer single-family homes with more space, privacy, and gardens over a unit in a triplex that has a shorter commute.

Moreover, realtors report a recent trend of city dwellers wanting to move to single-family neighborhoods in the suburbs to escape dense living conditions, which contribute to the spread of COVID-19.

Over time, the bill would cause the supply of single-family homes to diminish due to conversions to duplexes, "fourplexes", or “sixplexes” and the price for the remaining single-family dwellings would become even more expensive. This would make it more difficult for residents to attain their preferred lifestyle.

SB-9 could result in a range of destabilizing economic consequences. The purchase of a home is typically an individual’s largest investment. Establishing a state policy that permits unlimited and radical developments on adjacent parcels with no public process will destabilize single-family neighborhoods. Those concerned about protecting the value of their investment, and/or seeking to obtain/preserve the traditional benefits of single-family neighborhoods (less noise, traffic, etc.) will opt to move to more rural settings—contributing to additional sprawl—or add to economic and social divisions by increasing demand for living in homeowner’s associations where such activities would be prohibited via CC&R’s, or is the final straw that accelerates a move out of state. Business location and employee retention will likely be affected as well, since local quality-of-life is often a major factor for those making relocation decisions.

SB-9’s vast up-zoning, without any environmental review of potential adverse impacts and cumulative effects, is reckless.

The 2007 Marin Countywide Plan’s (CWP’s) Environmental Impact Report (EIR) projected potential growth of 14,043 more housing units (more than the current number of homes in Sausalito and Mill Valley combined) and 29,759 more residents, if land vacant in 2006 were fully developed according to zoning designations of the cities in Marin County and the Countywide Plan. This didn’t include density bonuses. Alarmingly, the EIR concluded that “land uses and development consistent with the CWP would result in 42 significant unavoidable adverse impacts”, including worse traffic congestion and insufficient water supplies.

There are more than 61,200 single-family dwellings in Marin, according to a 2006 report by the County Assessor-Recorder. The County’s average household size is 2.35 people (per the CWP’s EIR). So, potential growth consistent with SB-9, in which single-family homes turn into duplexes or four homes, could be up to 183,600 more homes and 431,460 more residents, over and above the CWP EIR’s forecast. If single-family homes turn into eight-unit complexes, then potential growth could be up to 428,400 more homes and 1,006,740 more residents. Such expansion is unsustainable.

SB-9’s subsequent housing density, population growth and changes to development standards would increase the risk of adverse impacts on the environment, public health and safety, traffic congestion, infrastructure, utilities (water supply), public services (schools), views, sunlight, privacy, neighborhood character, and quality of life.

Especially worrisome, the bill would jeopardize fire hazard zones. There are many communities in “high” and “very high” fire hazard zones that have steep, narrow, winding streets and few roads out to safety. The bill allows a dramatic increase in population in these hazardous communities, while reducing or eliminating parking requirements, which will lead to streets being overcrowded with parked cars. Dire consequences could result during an emergency when residents are unable to evacuate and fire trucks or paramedics are unable to reach their destinations.

Finally, SB-9 would create unfunded mandates. There is no funding for dealing with the above listed impacts and the bill provides an official sidestep of addressing this issue.

If you agree, please contact Marin County's Supervisors (; Marin County Council of Mayors and Councilmembers' (MCCMC's) Legislative Committee (; Senator Mike McGuire ( 415-479-6612; and Assembly Member Levine ( 415-479-4920 and urge them to oppose Senate Bill 9.


Senate Bill 9, Senator Atkins, Senator Mike McGuire