Planning Commission updates general plan water and wastewater map; recommends City Council approval

The San Luis Obispo Planning Commission voted unanimously to recommend that City Council approve an amendment to the General Plan’s water and wastewater element that updates the city’s wastewater capacity‑constrained area map, Special Projects Manager Shauna Scott told the commission.

The amendment updates which San Luis Obispo neighborhoods are subject to the city’s wastewater flow offset program and reflects data from December 2023–March 2024 peak wet‑weather monitoring and new hydraulic modeling.

Shauna Scott, Special Projects Manager with the Public Utilities Department, told commissioners the water and wastewater element dates to 1987 and that the 2018 update had incorporated a capacity‑constrained map based on older studies (2012 flow study and 2016 renewal strategy). Scott said the updated map was prepared by consultant West Yost using additional elevation data, current inspection records from the city’s Sewer Lateral Inspection Program, and flow monitoring collected during wet weather in December 2023–March 2024.

Scott said the model identifies two primary areas to be included in the updated capacity‑constrained map, retains some previously identified boundaries with minor adjustments (Area 1), and shifts a formerly downtown constrained area northward (Area 3). Staff recommended removal of the Laguna Lake area from the constrained map based on capital investments and lateral replacements completed since the earlier study.

The amendment does not change goals, policies or programs in the General Plan element; instead it replaces the capacity‑constrained map and updates text to reflect the current wastewater study and the city’s newly completed water resource recovery facility (staff noted a ribbon cutting was scheduled the coming Friday). Scott briefed commissioners that parcels within identified constrained areas are subject to the city’s wastewater flow offset program (municipal code section 13.08.396) and that the city has a sewer lateral inspection program (municipal code section 13.08.395). Staff estimated about 13,421 private sewer laterals exist within the city.

During the discussion commissioners asked how being within a constrained area affects property owners and what qualifies as a development triggering offsets. Scott said projects that increase plumbing fixtures or otherwise intensify wastewater generation as defined in the code must offset added flow, typically through private sewer lateral replacement or contribution to capital projects; staff described the offset calculation as effectively a direct nexus and said the city is considering rebate and inspection incentive programs to encourage property owners to document lateral condition.

Interim Public Works and Utilities Director Aaron Floyd and Deputy Director of Wastewater Chris Lehman answered technical questions about pipe materials, root intrusion and how drought‑related groundwater changes can increase infiltration into laterals. Scott told the commission the updated map was presented to City Council at a study session on Aug. 19, 2025 and council directed staff to proceed with the amendment process; staff said related ordinance changes and rebate/inspection proposals would return to Council for additional consideration in 2026.

After questions, a motion to recommend Council approval and the CEQA categorical exemption was made and seconded. The Planning Commission called the roll; the vote was yes: Commissioner Cooley, Commissioner Khan, Commissioner Flores and Chair David Houghton. Staff said the amendment is supported by CEQA categorical exemptions sections 15307 and 15308 because the map is intended to protect natural resources and the environment by reducing inflow and infiltration and the risk of sanitary sewer overflows. The Planning Commission’s action was a recommendation to City Council; final adoption will occur at a Council hearing.