Secondary residential units are now prohibited in some SLO County towns. Here’s where
The California Coastal Commission unanimously voted to prohibit secondary dwelling units in two San Luis Obispo County communities — officially stamping out any hope for additional residential growth in those areas for the time being.
The commission’s vote came Friday during its monthly meeting, which was held virtually.
Accessory dwelling units (ADUs) are now banned from being built in Cambria and Los Osos, although they are allowed in other areas of the county.
ADUs are small house-like developments — commonly referred to as “granny flats,” “in-law units,” “backyard cottages” and more — that local governments must allow, to an extent, to help ease California’s affordable housing crisis.
A chief concern for the state agency in allowing ADUs in Cambria and Los Osos was drinking water supply.
“The lack of a sustainable water supply in Cambria and Los Osos ... is well known to the Commission and the county,” said Commission coastal planner Esme Wahl during Friday’s meeting. “There, even existing water extractions to serve existing development have led to coastal resource degradation, including in terms of groundwater overdraft, seawater intrusion, fishery impacts and ESHA (environmentally sensitive habitat area) damage.”
Both communities have struggled for several decades to maintain viable water supplies despite ongoing conservation, seawater desalination, recycled water and groundwater recharge efforts.
Cambria’s population is served by four wells that tap into the groundwater beneath the San Simeon and Santa Rosa creeks. Its water source fluctuates greatly depending on how much rain the community receives, but there has not been enough to comfortably allow more development in the community since 2001, when a moratorium, with a few exceptions, on new water connections was established.
Los Osos residents get their water from three purveyors who tap into the Los Osos groundwater basin. When development in Los Osos exploded in the 1970s, septic systems polluted the basin, and overdraft of the basin caused severe seawater intrusion.
Despite several years of conservation programs and the installation of a new sewer system, the basin has not yet been deemed sustainable for the community’s current population, nor a growing one.
Some debate over commission’s ban on ADUs in Los Osos
San Luis Obispo County Planning and Building Department division manager Airlin Singewald said the county accepts the Coastal Commission’s modifications to its originally proposed ADU ordinance — which would have allowed such development in Cambria and Los Osos.
However, he noted mandatory retrofits to offset water use in ADUs built in Los Osos should have allowed for the units to be built.
“ADU development is a major component of the county’s roadmap to meeting affordable housing needs for all of its residents. In Los Osos, in particular, ADUs are required to offset their water demand on a two-to-one basis for the county’s retrofit-to-build program,” Singewald said during Friday’s commission meeting. “This means that any ADU built in Los Osos would actually reduce water demands on the groundwater basin, or at a minimum, would not be expected to increase demand on the basin.”
Several community members have recently raised concerns over the effectiveness of such offsets. The county has hired a consultant to analyze how the offsets impact the groundwater basin, the results of which have not yet been released.
Real estate broker Jeff Edwards commented during Friday’s Coastal Commission meeting to voice his opposition to the ADU ban in Los Osos.
“Our total demand is substantially less than the safe yield of our basin and the staff report fails to mention the robust Title 19 retrofit-to-build program in the County of San Luis Obispo at a two-to-one ratio of savings to demand,” Edwards said. “This represents water-neutral development. So any assertions that these projects are adding water use is simply misplaced.”
Los Osos does not yet have sustainable water supply, report shows
The 2020 annual report that examined the state of the Los Osos water basin determined that groundwater extractions from the basin were at 73% of safe yield.
The report also notes that despite the community achieving water use below the safe yield, seawater intrusion has continued to infiltrate the community’s freshwater supply.
Some community members called into the Coastal Commission’s meeting to encourage a ban that extends beyond ADUs because of the dire water situation, particularly in the Los Osos community.
Patrick McGibney of the Los Osos Sustainability Group, a grassroots organization that fights against any water-using development in Los Osos until there is proof the community’s water supply is sustainable, said the Commission should consider a ban in both communities on all water-using development — no matter how small.
“The amendment you’re considering today will prohibit ADUs within the imperiled Los Osos, Cambria coastal zone to help protect this valuable resource,” McGibney said. “The county realizes this and is recommending applicants apply for guesthouses instead, knowing that they have no oversight and can be easily transformed into an ADU after the fact.”
Several guesthouses have been constructed in Los Osos in recent years. Guesthouses, unlike ADUs, can only be built with a bathroom and wet bar, not a full kitchen.
One such guesthouse currently under construction on Highland Drive in Los Osos is being challenged in court because the county allegedly approved the development without proper public review. The lawsuit also raises concerns that the guesthouse will use water from the over-stressed basin.
Singewald noted that the county is greatly anticipating the Coastal Commission’s decision on its Los Osos Community Plan — which proposes 30% growth in the community by 2040, as long as the basin is deemed sustainable, which it has not yet been.
Commission staff said they hope to have a report on the plan for commission approval in the next several months.
This story was originally published February 16, 2022 at 5:00 AM.
