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North San Luis Obispo County, CaliforniaUpdated

InsideWells, water quality, the groundwater basin, septic, tanks, fire and the house

Ranch House Water

Town notesPaso Robles, Templeton, Atascadero, San Miguel, Creston and Shandon

Wells, tanks, septic and pipes on rural land around Paso Robles

Section front · Septic

Septic: The System Under Every Ranch-House Yard

Septic systems in north San Luis Obispo County serve nearly every rural home outside the town sewers, and the county's own program sets the rules they live by.

Updated

Stories

In brief

Round moss-spotted concrete septic tank lid with two metal lifting handles and a short vent pipe, set among dry tan grass beside a fallen evergreen branch
A concrete septic tank lid with its vent pipe in dry grass.

Beyond the sewer lines of Paso Robles and Atascadero, almost every house on a ranchette, vineyard parcel or oak-covered hillside sends its wastewater to a tank and a leach field in the yard. That system sits a short walk from the private well many of the same households drink from. This section covers how those systems are permitted and cared for in the unincorporated north county, what failure looks like, and the one hazard that kills people who get too close.

What this section covers

The rules start with the county. San Luis Obispo County's septic program was approved by the Central Coast Regional Water Quality Control Board on September 25, 2020, and permits run through County Planning & Building. Our story on septic systems on rural lots explains how a system works, who issues permits, why a parcel with both septic and its own well needs at least 2.5 acres, and where the state's setback numbers come from.

When something goes wrong, the yard usually says so first. Signs of septic trouble walks through what the U.S. Environmental Protection Agency lists as warnings, from gurgling drains to bright green grass over the leach field in a dry August, and who to call.

Some parts of the north county carry stricter rules. Creston, Templeton North, Shandon and a few other areas require nitrogen-reducing systems for new construction, because nitrate from septic effluent can reach the groundwater wells draw from. That is the subject of nitrogen-reducing septic areas.

Upkeep and safety

Two short briefs cover routine work. Septic pumping and inspection gives EPA's intervals, what the county expects a pumper to report, and the records worth keeping. Septic tanks are confined spaces explains why no one should go into, lean into or reach far into an open tank, and why the right response to a person collapsed inside is a 911 call, not a rescue attempt.

How we handle the facts

Every rule and number on these pages comes from the county, the state water boards, EPA or federal health agencies, linked where it appears. The county's full septic plan text was not fully readable to us, so where a local figure is missing we say so and point you to County Planning & Building. Readers with a well should also see our stories on nitrate in well water and testing your well water.

Where to call

  • County of San Luis Obispo, Planning & Building, Onsite Wastewater Treatment System Services — septic permits, repairs, the county septic program and pumping reports. Their official page
  • Central Coast Regional Water Quality Control Board — the regional approval of county septic programs. Their official page
  • Contractors State License Board — check that a septic contractor holds a C-42 Sanitation System license. License check
  • Emergencies — anyone overcome in or near a septic tank: call 911 and stay out.