Sweetwater Authority braces for up to 12% rate hike to fund PFAS mitigation

Sweetwater Authority braces for up to 12% rate hike to fund PFAS mitigationThe California utility is evaluating advanced treatment alternatives at its Perdue Water Treatment Plant as it kicks off a new cost of service study to absorb impending compliance costs.

A board director noted staff estimates that PFAS mitigation could drive a 6% to 12% water rate increase.

Carollo Engineers is conducting bench-scale testing for the Perdue Water Treatment Plant, evaluating options including GAC and ion exchange.

The utility has initiated its 2026 Water Rate Cost of Service Study with consultant NBS to establish new rates effective January 2027.

The board is considering supporting state legislation (SB 1313) that would authorize grants and loans for PFAS treatment projects.

Sweetwater Authority is bracing for a potential 6% to 12% water rate increase to cover the costs of mitigating per- and polyfluoroalkyl substances (PFAS), as the California utility begins a comprehensive review of its rate structure and treatment alternatives. The financial warning was highlighted by Director Elizabeth Cox, who cited staff estimates regarding the impending costs of PFAS remediation. "I was reading... about PFAS and the cost of mitigation and was reading staff had said 6 to 12% water rate increase could be possible," Cox stated, pressing for a revised schedule for the agency's upcoming rate study. The potential hike coincides with the launch of the utility's 2026 Water Rate Cost of Service Study, led by consultant NBS and project manager Sara Mares. The study aims to establish new water charges effective January 1, 2027. According to a staff report, the consultant will evaluate alternative rate designs, including adjustments to the balance between fixed meter charges and variable commodity charges, and the potential adoption of a three-tier residential rate structure. Concurrently, Sweetwater is advancing a pilot project and preliminary design report for PFAS treatment at its Perdue Water Treatment Plant. Carollo Engineers, which was awarded a $1.5 million contract for the study in December 2025, is currently conducting bench-scale testing using water samples from the facility. The testing includes rapid small-scale column testing to evaluate ion exchange (IX) and granular activated carbon (GAC) media. The utility is evaluating four treatment alternatives for the Perdue plant: - Blending with aqueduct water to lower PFAS levels. - Blending combined with powdered activated carbon (PAC) addition and enhanced coagulation. - Enhanced coagulation followed by a GAC contactor. - A GAC contactor with IX vessel polishing. The alternatives vary significantly in capital and operational costs. While the GAC and IX options eliminate reliance on imported water, they carry the highest operational complexity. Carollo is scheduled to deliver a final preliminary design report by October 2026. To help offset future compliance costs, the governing board is also considering a support position on California Senate Bill 1313. The legislation would authorize the State Water Resources Control Board to fund PFAS projects through grants or loans, providing a potential funding mechanism for the impending infrastructure upgrades.