Moulton Niguel targets direct potable reuse as Colorado River cuts loom

Moulton Niguel targets direct potable reuse as Colorado River cuts loomThe California district is updating its long-range reliability policies to include a 15% local supply target via advanced recycling, as reliance on Metropolitan Water District becomes increasingly precarious.

Staff recommended a new policy to evaluate direct potable reuse (DPR) to meet up to 15% of local water demand.

The 2025 Long-Range Water Reliability Plan anticipates a 200,000 acre-foot reduction in Metropolitan Water District's Colorado River supply.

District water demand has continued to decline below 2020 levels despite development projections.

The Board is scheduled to vote on the updated reliability policy in March 2026.

Moulton Niguel Water District (MNWD) is preparing to formally evaluate direct potable reuse (DPR) as a component of its future water portfolio, following a February 9 presentation of its 2025 Long-Range Water Reliability Plan. Staff recommended the Board adopt a new policy to evaluate DPR opportunities to develop "up to 15% of local water supplies" when the item returns for a vote in March. This proposal leverages state regulations finalized in late 2023 that allow purified wastewater to be introduced directly into drinking water systems, bypassing the environmental buffers required for the indirect reuse projects historically common in the region. The strategic shift comes as the district assesses risks to its imported supplies from the Metropolitan Water District of Southern California (MWD). Laura Rocha, MNWD’s Water Resources Manager, highlighted the uncertainty surrounding the post-2026 operating agreements for the Colorado River. Rocha noted that MWD, as a junior rights holder, is anticipating "at least a 200,000 acre-foot reduction" in its Colorado River supplies in current projections. This volatility has similarly prompted the regional wholesaler to advance its own massive recycling initiative, Pure Water Southern California, marking an evolution from its decades-long focus on incentivizing groundwater recharge and indirect reuse. "The further you get out, the murkier it is to see what those supply projections will look like," Rocha told the Technical Administrative Committee. While the district currently holds 43 days of emergency supply—within its policy target of 31 to 60 days—the potential for increased shortages on the regional network is driving the interest in local recycling. Demand forecasting presented at the meeting showed a continued downward trend in consumption, defying population growth assumptions. "In 2020, I honestly thought... we can't go much lower, and yet we have in the past 5 years," Rocha observed. The district’s demand remains well below its state-mandated Urban Water Use Objective. The updated reliability plan serves as a precursor to the district’s 2025 Urban Water Management Plan, which is due to the state by July 1, 2026.