Washington County, Utah is pushing forward with a more than $100 million expansion of its primary water treatment plant, a project that underscores just how precarious water supply has become in one of America's fastest-growing desert communities.
The Washington County Water Conservancy District, which supplies water to St. George and surrounding communities, is seeking construction bids for Phase 3 of the Quail Creek Water Treatment Plant expansion. The project will boost the plant's capacity to 90 million gallons per day, roughly double what it can treat today, and add ozone disinfection technology that handles contaminants and algae-related taste-and-odor problems more effectively than conventional chlorine treatment.
The stakes are hard to overstate. Washington County's population has more than doubled since 2000, climbing past 190,000, and projections point toward 500,000 residents by 2060. All of this growth is happening on the edge of the Mojave Desert, where annual rainfall averages about 8 inches and the region depends almost entirely on the Virgin River system and limited groundwater. The Quail Creek Reservoir, the county's main surface water storage, was originally built in 1985 and rebuilt after a catastrophic dike failure in 1989 sent 25,000 acre-feet of water rushing downstream.
For years, the district's long-term answer to the supply crunch was the Lake Powell Pipeline, a proposed $2 to $3 billion project that would pump Colorado River water 140 miles to Washington County. That pipeline faces mounting legal, regulatory, and financial hurdles, and its future is deeply uncertain. A 2020 Utah legislative audit questioned the district's demand projections, and the federal government signaled skepticism during the Biden administration. Meanwhile, a 23-year megadrought on the Colorado River basin left reservoir levels dangerously low before partial recovery in 2023 and 2024.
With the pipeline in limbo, maximizing what the county can squeeze from its existing sources has become essential. The ozone addition is also a response to real and growing water quality pressures: warming reservoir temperatures have fueled more frequent algal blooms at Quail Creek, and tightening EPA standards for contaminants including PFAS are pushing utilities toward more advanced treatment technology nationwide.
The district has also faced scrutiny over St. George's historically high per-capita water use, which once exceeded 300 gallons per person per day, though the agency reports significant reductions in recent years through conservation pricing.
With design work already complete, the district is now in the construction bidding phase. How quickly the project moves forward will depend on contractor selection and final pricing, but the expansion represents the most significant upgrade to Washington County's water infrastructure in decades.
