The National Pollutant Discharge Elimination System (NPDES) is a five-year term permit issued to MVSD by the San Francisco Bay Regional Water Quality Control Board (RWQCB). The NPDES permit governs the discharge of treated wastewater to the environment with the goal of protecting the environment, public health, and beneficial uses of water bodies. The permit includes conditions, monitoring requirements, and limitations for pollutants. 

Every five years, MVSD must apply for a new NPDES permit, at which time, the past five years of water quality data are compiled and evaluated to ensure the existing limitations continue to be protective of the environment or whether new or more restrictive limitations are needed. MVSD completed this application process and a new NPDES permit was adopted by the RWQCB in December 2021.

New NPDES permits additionally incorporate requirements for complying with any other applicable regional, state, or federal policies or regulations that were developed during the previous five years. MVSD’s new NPDES permit includes several new requirements, including a significantly lowered ammonia limit, a new compliance monitoring location, and increased chronic toxicity monitoring. MVSD also continues increased nutrient monitoring to find a way to leverage the nutrient-reducing capacity of Moorhen Marsh in advance of forthcoming new nutrient limitations.

It is MVSD’s mission to protect the public health and environment in a safe and reliable manner, at a reasonable cost. This mission is at the forefront of staff’s minds when strategizing how to best meet the requirements of the NPDES permit.