Help protect and preserve the Los Osos groundwater

Dear neighbors and friends,
We are reaching out to you to update you on our dire water situation here in Los Osos. You likely know that our sole water source is the water basin below us, which for over four decades has been in overdraft. A Level 3 severity was declared in 2005. Seawater has moved in as we have pulled out more freshwater than is going back in, whether through precipitation, irrigation septic system return flows, or recharge of treated wastewater.
Los Osos has had  a “building moratorium” in place since the 80’s imposed by the regional water board until we replaced our septic systems with a sewer.  However, our septic systems were also helping to recharge our water basin. Without getting too technical, we still have nitrates in our upper aquifer and seawater intrusion in our lower aquifers, and the greater the demand (water use) on the Basin the more likely it is that the Basin will reach a tipping point and we lose the Basin as a viable water source.
As a community, we have stepped up to the plate and lowered our water use to help stop seawater intrusion. Per capita water use went down to around 50 gallons per person per day for several years, but this year is up around 70 gallons per day, probably due to more people being at home during the pandemic.
Besides the threat of seawater intrusion, the Basin is facing a threat from County plans to add 30% more development. The Los Osos Community Plan (LOCP) was adopted by the County Board of Supervisors on December 15, 2020 but has not yet submitted the plans to the Coastal Commission for certification.  The LOCP sets a build out limit for the community and standards for approval of development, some of it subject to a growth rate restriction (Growth Management Ordinance—GMO) and some “exempt” from the restriction. The plan allows about 1800 new housing units (possibly more with “exempt” housing).  This will mean an increase population of 4000 people or more. Although some of this increase will occur over 20 years via the growth rate restriction (Growth Management Ordinance--GMO), much of the development will happen within the first few years. If the development further overdrafts the Basin--and there are good reasons to believe present Basin modeling overstates the “sustainable yield” of the Basin--it may be too late to stop irreparable harm to the Basin by the time the overdraft is known.   
This new development allowed by the LOCP will be in addition to the building allowed during moratorium outside the sewer service area. The recently-released 2020 census reports a population increase of 14% in Los Osos since 2010.  Areas where new development continued include Cabrillo Estates, parts of Bayview Heights, east of South Bay Boulevard, along Pecho Road, and a few other areas. All of this new development pulls water from our shared basin.
Within the sewer service area, the County also began permitting auxiliary dwelling units (ADU’s), remodels with bathrooms, and mobile home additions in Morro Shores mobile home park, which add to water use.
The Basin Management Committee’s Annual Monitoring Reports show seawater intrusion is still occurring, and a recent technical memorandum shows nitrates from homes that are not hooked up to the sewer may be polluting supply wells that part of the community relies on. These are two reasons we say the County should provide conclusive physical evidence (reliable monitoring data) confirming the Basin is sustainable for the current and future development before going forward.
The three Los Osos Water purveyors, the LOCSD, Golden State Water Co., and S&T Mutual Water Co., have also expressed concern about the County’s rush to development without sufficient physical evidence (metric and monitoring data) confirming Basin sustainability.  At least one purveyor has said the Basin is not sustainable under current conditions and another has expressed concern that water customers have not paid for Basin Plan programs with increased water rates to support development.
The County is approving development currently by requiring applicants to retrofit existing homes and businesses to reduce water use; however, this uses conservation potential that may be needed to provide a sustainable water supply for the current population, and it doesn’t ensure a sustainable water supply for the new development.
As a community, we need to stand together to stop the rush to develop the area until hard data shows the Basin is sustainable.  We also need to insist that the County does what the wastewater project permit and Basin Plan require it to do: “help Basin residents to reduce their potable water use as much as possible” and stop and reverse seawater intrusion to ensure a sustainable water supply for the current population as a first priority—before adding development or importing water.  Imported water is scarce when needed most (e.g., during droughts) and bringing it now will only shift focus and resources away from saving the Basin. Until the County follows through on commitments and the Basin is shown to be sustainable for the current and added development, neither the County nor Coastal Commission should approve added new development.
We have hired an attorney for advice and to help with the legal aspects of our concerns. We also need to hire expert consultants to verify specific concerns we have regarding the current and future condition of our Basin.  This is expensive, and we ask for you to join us in supporting effective management of the Basin to preserve, protect, and restore our only water source, a relatively inexpensive, ancient, and irreplaceable natural source, on which the sustainability of the community, area farms, and high-value sensitive habitat in the area depend.
Now is the time to speak out against water and land use practices that could change the quality of life in Los Osos forever.  Please go to our website and get involved.  If you have any questions, our contact information is on the website.


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Los Osos Sustainability Group 
Los Osos, CA
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