Truckee Meadows Water Authority details supply mix, storage and reuse plans

John Zimmerman, General Manager of the Truckee Meadows Water Authority, told the Nevada Assembly Committee on Natural Resources that TMWA serves roughly 135,000 connections and that about 80% of its supply is surface water from the Truckee River. "We have about 89,000 acre‑feet served in 2024," Zimmerman said, describing a supply mix of Truckee River surface water, production wells for peak demand and a recently built Whites Creek treatment plant used for summer deliveries and aquifer recharge.

Zimmerman summarized the benefits of the Truckee River Operating Agreement (TROA), which he described as a multilateral compromise that provides drought supply stability while allocating additional fish credits to the Pyramid Lake Paiute Tribe in good water years. He said TROA lets parties store water during the October–March storage season and then allocate it depending on whether the water year is wet or dry.

The presentation covered TMWA's infrastructure and planning: two main treatment plants, a network of more than 279 pump zones, three older run‑of‑river hydroelectric plants (which Zimmerman said produce about $3,500,000 in revenue and reduce customer costs by 3–5%), and plans for a new hydroelectric facility at Chalk Bluff to generate about 1 megawatt behind the meter.

Zimmerman described aquifer storage and recovery as a core drought resilience tool: treated Truckee River water is recharged into aquifers in winter and retrieved during peak summer demand. TMWA is updating its water resource plan for 2025–2045 and said prior modeling (using eight global circulation models) did not show system shortages before 2069 provided the system could call for at least a 10% conservation level.

On reclaimed water and reuse, Zimmerman said TMWA is a drinking water provider and does not operate wastewater plants but works with wastewater agencies on effluent management. He described an "indirect potable reuse" project in the North Valleys (the American Flat project) that would take treated effluent from the City of Reno's Reno‑Stead plant, advance it to A‑plus quality, inject it into the aquifer and later recover it for potable use. Zimmerman said a pilot step will irrigate a farm to demonstrate safety and that a larger project would include injection for future use; he estimated the North Valleys advanced treatment project at about $240,000,000.

Committee members asked how bridge or road projects affect river operations and whether storage could be increased. Zimmerman said the agency is engaging with the Bureau of Reclamation and Army Corps of Engineers on forecast‑informed reservoir reoperation to capture earlier runoff and to work around flood‑control constraints. On turf policy and cash‑for‑grass programs, Zimmerman said local governments in Reno, Sparks and Washoe County still allow turf and that conserved turf irrigation often contributes to basin recharge — he said a comparable statewide cash‑for‑grass campaign like Southern Nevada's would face structural and legal differences because return‑flow and river decree rules on the Truckee River limit how conserved water can be repurposed.

Members also asked about developer water rights and TMWA's Rule 7 water bank. Zimmerman said developers can purchase allocations from the authority's inventory (developers do not buy the underlying water right; they buy a commitment/allocation), and TMWA maintains water rights inventory and a roughly 2,000 acre‑foot Rule 7 bank for smaller or rapidly timed projects. He said committed rights are not re‑restated for other uses once allocated.

The committee did not vote on any measures; Zimmerman closed the presentation after a question period.