During California’s recent drought from 2020 through 2022, the Las Virgenes Municipal Water District (LVMWD, District), amongst many other agencies, was faced with unprecedented reductions in available water supplies. LVMWD’s water supply was curtailed a staggering 73% by water wholesaler Metropolitan Water District of Southern California (MWD). Entering a third year of drought with no end in sight – and with drought messaging, pricing incentives, and monetary penalties having limited success – LVMWD developed its Flow Restrictor Program (FRP).
LVMWD, a retail water agency situated geographically within the Santa Monica Mountains, provides water, wastewater, recycling water and composting services to an area with scarce local water supplies. The District is a member agency of Metropolitan Water District (MWD), and the California State Water Project (SWP) is the District’s sole water supply.
In conjunction with LVMWD’s unique geography, the District serves a demographic with substantially higher income levels than the average or median for the State of California (and most other parts of the country). As a result, some customers have no qualms about paying hundreds or even thousands of dollars every month for their water service and even indicated that mandates to conserve water do not apply to them. Conducive with this mindset, high household incomes, and large lots that require lots of water, water consumption has been historically high.
In 2016, to address issues regarding efficient water use and conservation requirements during the 2014-2017 drought, the District developed and implemented “water budgets” to address inequities associated with tiered water rates. The development of water budgets proved helpful in determining when a customer is being “wasteful”. Being able to identify wastefulness using each customer’s monthly water budget as a benchmark was important for the success of the FRP.
Though the development of water budgets sought to address inequalities in water consumption for customers, the 2020 through 2022 drought proved to be a difficult time for the District that required further measures for conservation. In late 2021, after two years of internal drought response and the prospect of a third dry year, LVMWD modified its Administrative Code, establishing new thresholds for determining when a customer is considered wasteful depending on what stage of the Water Shortage Contingency Plan (WSCP) is activated. The new threshold or exceedance level is 150% during a State 3 declaration and 120% for a Stage 4 (LVMWD’s highest stage of drought). In November 2021, the Board of Directors escalated the WSCP from Stage 2 to Stage 3, which called for mandatory conservation.
During the Covid-19 pandemic, LVMWD used flow restrictors on customer accounts to help keep unpaid bills to a minimum. The program was largely successful and got staff thinking about the potential of using flow restrictors for water conservation. Though it had never been done before, drastic measures were needed to assist in the exceedingly high conservation measures. The reduction target in 2022 equated to a whopping reduction of 35% from water use in 2020 and over 50% reduction from water use compared to 2013. By June 1, 2022, the District was allocated 73% less water compared to historical amounts.
To handle the catastrophic cut in allocations, the Board of Directors unanimously approved the concept of the Flow Restrictor Program on November 16, 2021. Seeing as there were no tried and true best practices to use as a template, it was now up to LVMWD to lead in this new and innovative approach to help meet conservation objectives during the drought emergency. After initial planning, staff drafted the 2022 Flow Restrictor Device Implementation Plan. As per the WSCP, when in Stage 3, the threshold for being considered wasteful and subject to a flow restrictor is 150% of a customer's monthly water budget. A first-time exceedance called for a warning on that customer’s bill stating that they could be subject to penalties of up to $10 per unit of water above the exceedance threshold, plus the installation of a flow restrictor for continues exceedances. A hard and email copy would be delivered after the 2nd and 4th exceedances. If customers still exceeded their budget after a total of seven occurrences, they may receive a flow restrictor device at any time depending on where they land in the pecking order. The more acute offenders were prioritized. However, with installations still at 20 devices per week, some customers would luck out and avoid getting a device installed depending on the magnitude of other exceedances.
The installation of flow restrictors was both punitive and with the intention of reducing water waste. Once installed, the device would remain in place for 14 to 30 calendar days for first time offenders, 90 days for second, and 180 for third and subsequent offenders. The hope was that in receiving a device, the customer would be inconvenienced and change their wasteful behavior. If customers continued to ignore the call for efficient water use, the device would remain in place for a longer time. Finally, the flow restrictor would not be removed prior to the established duration, even by way of paying another fee to have it removed earlier.
By the first round of 4th exceedance notices in May of 2022, customers started to significantly reduce their water use. From June through November, there was relatively consistent reduction in water use at an average of 37% compared to the same months in 2020. This slightly exceeded the District’s reduction target of 35%. By December of 2022, customers reduced their water use by 51%, increasing the average for June through the end of the calendar year to 39%.
It is important to note that different variables can impact conservation, and analysis of these variables was necessary to determine the amount of conservation likely associated with the FRP. One of these variables, the evapotranspiration rate (ET), can – and often does – affect how much water a customer uses on any given day. March of 2022 had a significantly higher ET than in the same month of 2020, while December of 2022 had a significantly lower ET than in the same month of 2020. The difference in ETs explains and increase in water consumption in March and a high conservation level in December. However, there were months in June that had significantly high conservation rates despite the ET being higher. This indicates that customers started using less water because of the call for conservation, not because of weather differences that impacted ET values.
The District collected information on water savings from other SWP-dependent agencies that also had robust messaging during the drought to discern the impact that flow restrictors had. These neighboring agencies were the City of Thousand Oaks, Oak Park via Triunfo Water and Sanitation District (TWSD), Newbury Park via California-American Water Company, and Westlake Village (Ventura County) via California Water Service Company. When analyzing the differences between LVMWD and neighboring agencies, LVMWD’s FRP appears to have contributed to a relatively small amount of additional conservation – 3.4% on average for the entire year. However, as LVMWD customers became more aware of the FRP as more customers received flow restrictors, the last three months of year indicate an average of 5.7% more conservation for LVMWD versus the comparison agencies.
The implementation of flow restrictors proved to be successful in helping align water use with available supplies or to get customers to use water more efficiently. An estimated annual average of 3.4% additional water conservation was achieved with the FRP. However, LVMWD tracked closer to 6% more conservation compared to similar agencies without FRPs after it had been in place for 9 months. LVMWD achieved additional conservation with the FRP with only a grand total of 208 flow restrictors installed (less than 1% of LVMWD’s customers). An additional amount of conservation with a higher number of installations could easily exceed 10%.
Currently, the FRP continues to be implemented. LVMWD customers used 30% less water year to date in 2023 versus 2020. For 2022, during the drought, customers reduced by 20% compared to 2020. Though this could be due to many reasons including messaging, the use of the FRP is a contributing factor.
