The Delta Diablo Board of Directors held a public hearing on Thursday, June 26, 2025 to consider adoption of proposed Sewer Service Charges (SSCs) rate increases for wastewater utility services. After the public hearing, the Board of Directors adopted an ordinance establishing SSCs for ​Fiscal Year 2025/2026 (FY25/26) (July 1, 2025-June 30, 2026) and setting maximum allowable SSC increase​s for FY26/27 through FY29/30.  A summary of the adopted rates and associated financial needs and information are provided below. In addition, related fact sheets are available below.

What Services Does Delta Diablo Provide to Customers?
Delta Diablo (“District”) provides wastewater conveyance and treatment services for approximately 73,273 customer accounts (residential and non-residential), representing over 218,000 residents in the cities of Antioch and Pittsburg, and the unincorporated community of Bay Point. As part of our core mission to protect public health and the environment, the District treats 14.0 million gallons of wastewater each day with a focus on exemplary regulatory compliance, innovative and sustainable approaches, and sound stewardship of the public’s resources and trust. The District has transformed its Wastewater Treatment Plant (WWTP) into a “resource recovery facility” by producing approximately 7.0 million gallons per day of recycled water, generating onsite renewable energy to meet over 50% of WWTP power needs, reusing biosolids as fertilizer, providing household hazardous waste (HHW) collection services, and further protecting the Delta by providing street sweeping services to remove pollutants that would otherwise enter local stormwater systems.

Why is Delta Diablo Proposing Rate Increases?

Adopted Five-Year Maximum Sewer Service Charge Increases for FY25/26-FY29/30

The District collects SSCs from its customers each year as the primary revenue source needed to fund capital infrastructure investments, labor, energy, biosolids, chemicals, regulatory compliance, infrastructure maintenance, and Delta HHW Collection Facility operations. For FY25/26, the District adopted SSC increases of approximately 8.5% per year (+$40.25) for residential customers in Antioch/Pittsburg, and approximately 8.8% (+$57.35) for residential customers in Bay Point. In FY26/27 through FY29/30, the District adopted maximum SSC increases of 8.5% and 8.5% for Antioch/Pittsburg and Bay Point customers, respectively. The District continues to maintain rates below the average of peer agencies in the San Francisco Bay Area region.

In compliance with California Constitution Article XIII(D), Section 6 (“Proposition 218”), the FY25/26-FY29/30 maximum SSCs incorporate FY25/26 Cost-of-Service Study findings (prepared by IB Consulting), which updated growth in the service area and corresponding additional wastewater flow to the District’s WWTP. The Study is available at the District’s offices and website. SSCs for non-residential customers (i.e., commercial, industrial) were adjusted accordingly for FY25/26-FY29/30 based on customer class.

Most District customers are billed on a fiscal-year basis and pay SSCs via annual property tax bills. The District’s Board of Directors will consider approval of SSC increases for each future fiscal year, subject to the maximum SSC increases. Property tax bills also include a street sweeping service charge that varies by community based on service frequency

Delta Diablo is committed to fair and reasonable rates. As a not-for-profit public agency, state law only allows the District to recover costs necessary to operate and maintain our system and ensure that it is stable and safe for the future. SSCs are required to prioritize sustained capital investment to maintain the integrity of our aging infrastructure while ensuring sufficient funding to meet progressive increases in operating costs and associated regulatory compliance obligations.

The District has been recognized for excellence in financial reporting by the Government Finance Officers Association and is audited annually by an independent accounting firm. As an industry leader and progressive “Utility of the Future”, the District values community engagement, serving as responsible stewards of the public’s resources and trust, transparency, innovation, and workforce engagement and development to achieve its core mission of protecting public health and the environment.

The following documents are available for more information on the proposed SSC increases:

Delta Diablo Prop. 218 Notice: Proposed Five-Year Maximum SSC Increases

Delta Diablo Wastewater Cost-of-Service Rate Study

Delta Diablo FY25-26 SSC Increases Fact Sheet – April 2025

Delta Diablo Infrastructure Investment Fact Sheet – April 2025

Delta Diablo Nutrient Removal Regulatory Mandate Fact Sheet – April 2025

Delta Diablo Board of Directors Presentation on Proposed Maximum SSC Increases – June 26, 2025