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Alfred Merritt Smith water treatment facility

Water testing and treatment

We test water all over the valley

To ensure that our water meets or surpasses federal drinking water standards, the Water District collects and analyzes water samples with more frequency than federal regulations require.

In 2021, water quality staff:

  • Collected more than 50,000 water samples 
  • Conducted more than 318,000 analyses of those samples
  • Monitored water quality in "real time" 24 hours a day, 365 days a year

We also conduct extensive quality control sampling of our water distribution system, including reservoirs and pumping stations around the valley. New pipelines also are tested for bacteriological quality before they are accepted as part of the distribution system.

Although this type of sampling is not required by regulation, it's important for identifying the system's potential areas of weakness.

Water sampling stations

We manage 367 sampling stations where we draw water samples for required testing.

Some of these stations are above ground; others are installed in our customers' meter boxes to ensure that water quality is maintained all the way to the tap.

NOTE: Our employees will NEVER ask to enter your home to collect a water sample from your tap. Please see our "How to identify our employees" page for more information.

We treat drinking water to ensure its quality

Nearly 90 percent of our drinking water comes from the Colorado River via Lake Mead. The remainder comes from a deep groundwater aquifer beneath the Las Vegas Valley, which we use primarily during summer months to meet peak demand.

Treating water from Lake Mead

Water drawn from Lake Mead is treated at the Southern Nevada Water Authority's Alfred Merritt Smith Water Treatment Facility or the River Mountains Water Treatment Facility.

The treatment process begins with disinfection.

Water is disinfected using ozonation, a treatment process that destroys bacteria and other microorganisms through an infusion of ozone. Ozone is a gas produced by subjecting oxygen molecules to high electrical voltages.

Next, the water is aerated to reduce odors and increase the water's oxygen content.

Microscopic particles are then combined through a process called flocculation. These larger, combined particles are removed through the use of a multi-layered filter composed of anthracite coal, silica sand and garnet sand.

As the water leaves the water treatment facilities, chlorine is added to protect it on the way to customers' taps. It also is treated to minimize pipeline corrosion.

Treating groundwater

Because it is naturally filtered, water drawn from the groundwater basin is simply treated with chlorine as it enters the distribution system.

For more details about how our water is treated to ensure its quality and safety, visit the Southern Nevada Water Authority website,