The South Valley Lateral delivers about 40% of Southern Nevada's drinking water, according to the Southern Nevada Water Authority, and the Authority's 2020 capital plan projected it to reach 95% of capacity by 2034 with no redundant feed. The planned answer is the Horizon Lateral Program, now estimated at US$2.0–2.7 billion for the whole program, against US$1,596.7 million in the 2020 plan.
What Phase I includes
Phase I is in final design, with construction expected to start in early 2027 and finish in 2030. Later phases will be built "as needed." The Authority says the program is meant to protect service for nearly a million existing customers and does not require new water resources. In May 2026 the Sloan Canyon Conservation and Lateral Pipeline Act became law, authorizing a tunnel under the Sloan Canyon National Conservation Area.
A system built for low water
The Horizon Lateral follows earlier projects that protected supply rather than adding it. The third Lake Mead intake, whose shafts and tunnel cost US$532.3 million, and the Low Lake Level Pumping Station let the Authority keep drawing water as the lake drops. In FY 2024 the system ran 175 miles of pipeline, 28 pumping plants and 1,000 mgd of ozone treatment capacity.
Paying for it
The FY 2026-27 tentative budget sets capital sources at US$705.3 million. On October 19, 2026 the Las Vegas Valley Water District priced US$498.6 million of new-money bonds for the Authority's capital plan, according to the sale listing. In May 2026 the Authority said the capital plan, including the Horizon Lateral, is already built into existing rates.
What the posted capital plan still leaves out, how governance and financing work across seven member agencies, and how federal Colorado River cuts affect the outlook are covered in the full report. The full report, Water Systems Overview: Southern Nevada Water Authority, is available for USD 499. For a free overview, read the Southern Nevada Water Authority Utility Snapshot.