Marin Water targets 10% reduction in commercial and institutional use under new state conservation rules

Marin Water targets 10% reduction in commercial and institutional use under new state conservation rulesThe district is subclassifying its non-residential customers to pinpoint inefficiencies, setting a baseline to capture nearly 380 acre-feet of savings and exploring a leak-detection partnership with a major state prison.

CII customers account for 19% of the district's overall water use, totaling approximately 3,800 acre-feet annually.

Staff are classifying accounts into 22 state-mandated categories, adding local subcategories to better target custom rebates and track usage outliers.

The district has established an internal goal to reduce overall CII water use by 10% from a 2025 baseline.

A unique partnership is being explored with San Quentin prison to utilize inmates for leak detection on the facility's aging water system.

To comply with California's incoming conservation mandates, the Marin Municipal Water District (MMWD) is undertaking a granular analysis of its Commercial, Industrial, and Institutional (CII) customer base to identify inefficiencies and drive down demand. During an August 25, 2026, Planning Committee meeting, Water Efficiency Manager Carrie Pollard outlined the district's strategy to meet the requirements of the State Water Resources Control Board's "Making Conservation a California Way of Life" regulations. The state framework requires utilities to classify all CII customers into 22 specific categories so that performance metrics can be established. CII water use currently accounts for 19% of MMWD's overall demand, or roughly 3,800 acre-feet based on 2025 data. Because the state's 22 categories are broad—grouping diverse users like sit-down restaurants and donut shops under a single "food service" umbrella—district staff have developed further subcategories to accurately benchmark water use metrics such as square footage or hotel room counts. "This initial pass was water use, and it's going to be a refinement over time," Pollard told the committee. "If they're a restaurant and they have all the right hardware and they're doing a good job, then pat them on the back and move on to someone else. Where are those sites that are inefficient that we can get some traction on?" The initial analysis identified lodging/residential, food sales and service, healthcare, and education as the top four water-using CII categories. The data also highlighted significant outliers, most notably the San Quentin prison, which accounts for 50% of the water use within the lodging/residential classification. Pollard noted that the prison operates an aging, leak-prone water system built on hard rock, making excavation and repairs challenging. To address the water loss, MMWD is currently in talks with the prison's rehabilitation program to train inmates to perform water monitoring and leak detection work on the facility's interior plumbing. To drive progress, MMWD staff have established an internal goal of a 10% reduction in overall CII water use, which would equate to nearly 380 acre-feet of savings. The district plans to leverage its custom investment rebate program, launched last year, to help businesses offset the capital costs of upgrading inefficient hardware like toilets and dishwashers. While the 10% reduction target is currently without a strict deadline, board members expressed strong support for the data-driven approach and requested that staff provide a proposed timeline for achieving the savings during their next quarterly water efficiency update.