Rules proposed to cut groundwater use in SLO County's unincorporated areas

A vineyard east of Paso Robles near Highway 46 begins to leaf out as unirrigated hillsides dry out in April.
A vineyard east of Paso Robles near Highway 46 begins to leaf out as unirrigated hillsides dry out in April. dmiddlecamp@thetribunenews.com

As an extreme drought drags into its fourth year and groundwater aquifers continue to dwindle, county planners are considering a sweeping new set of changes to land-use rules that will reduce groundwater extraction in unincorporated areas of San Luis Obispo County.

The county Planning Commission will hold a daylong hearing Thursday to consider the proposed changes that will affect water use in both new and existing development, as well as agricultural operations in areas of the county where pumping meets or exceeds the aquifer’s ability to replenish itself.

“Water levels in groundwater basins and surface lakes and reservoirs throughout the county have been in decline for over a decade, and current exceptional drought has exacerbated this decline,” county planner Xzandrea Fowler wrote in a staff report.

The basins that would primarily be affected by the new rules are the 12-square-mile Los Osos basin, the 27-square-mile Nipomo Mesa basin and 790-square-mile Paso Robles basin.

Groundwater is the sole source of water for Los Osos, and the sprawling Paso Robles basin provides water for 29 percent of the county’s population. The Nipomo Mesa uses a combination of groundwater and water piped in from Santa Maria.

An emergency ordinance that requires all new pumping from the Paso Robles basin to be offset by an equal amount of conservation is due to expire Aug. 27. The San Luis Obispo County Local Agency Formation Commission is processing an application to create a water management district for the basin that would manage groundwater use at sustainable levels. Landowners in the basin are expected to vote on whether to form the district in March.

Once the Planning Commission has completed its review of the proposed changes, they will be sent on to the county Board of Supervisors for final approval. No date for supervisors to hear the amendments has been set.

Some of the main proposed rules the commission will consider Thursday include:

  • Requiring that any new water use be offset through water savings from within the same water source.
  • Requiring that new development served by an individual well must have a well meter and verification of its installation.
  • Continuation of plumbing retrofit requirements that encourage replacing older, higher-water-use toilets and showerheads with more efficient fixtures.
  • Creation of a “cash for grass” program that would offer cash incentives for property owners to replace existing turf with low-water-demand landscaping. Water savings generated by the cash for grass program could be purchased by developers to comply with offset requirements.
  • Prohibition of activities defined as water wasting such as irrigating outdoor landscapes to the point that water runs off into non-irrigated areas and the use of hoses not fitted with an automatic shut-off nozzle.
  • Provisions to reduce agricultural water waste such as the use of covers to reduce evaporation from farm ponds and the use of wind machines for frost protection rather than using sprinklers.
  • Requirements that new landscaping use low water-using plants.
  • Already, several agricultural groups have lined up to criticize the changes as burdensome and counterproductive and are asking the commission to delete some of the proposed rules.

    Claire Wineman, president of the Grower-Shipper Association of Santa Barbara and San Luis Obispo Counties, said agriculturalists are concerned that the new rules could set a bad precedent and will have unintended consequences that could diminish farmers’ ability to grow crops. For example, the group opposes proposed requirements that new water wells be equipped with meters to monitor their water use.

    “We are absolutely committed to responsible water use but want to make sure that the rules are thoughtful,” she said. “The fundamental question is should the county regulate groundwater through land use when there are other entities that are a better fit for water use such as adjudication and water management districts.”