Southern Nevada currently reuses nearly all its wastewater, either through direct or indirect reuse. Direct reuse involves collecting, treating, and reusing wastewater flows for non-potable uses such as golf course irrigation or park use. Indirect reuse consists of recycling water by way of treatment and release to the Colorado River for return-flow credits.
The City of Boulder City, City of Las Vegas, Clark County Water Reclamation District, City of Henderson and City of North Las Vegas each operate wastewater treatment facilities that contribute to the region's direct and indirect reuse.
Recycled Colorado River water
Recycled Colorado River water has both environmental sustainability and cost advantages.
Direct reuse involves capturing, treating and reusing wastewater flows for non-potable uses such as golf courses or park irrigation.
The Southern Nevada Water Authority Cooperative Agreement notes approximately 22,000 acre-feet per year of water of direct reuse for power plant cooling, golf course irrigation and municipally operated common area landscape irrigation. Actual reuse varies from year-to-year.
Additional direct reuse does not extend Southern Nevada's Colorado River allocation because it will reduce or offset the water returned to Lake Mead, for return flow credit.
Indirect reuse consists of recycling water through the wastewater treatment facilities and releasing it back to Lake Mead for return flow credits.
Approximately 40 percent of water used in the Southern Nevada Water Authority's service area is recycled. Of that, about 90 percent is indirectly recycled through return flow credits.
Current recycled water resources
The following describes current recycled-water activities among the Southern Nevada Water Authority (SNWA) member agencies. For more details, see our Water Resource Plan.
In Laughlin, the Big Bend Water District is the potable water purveyor. The Clark County Water Reclamation District provides recycled water to Laughlin and is currently supplying recycled water for dust control at a local landfill.
A portion of Boulder City's treated effluent is sold and used at sand and gravel operations, up to 400 acre-feet per year.
The Water Pollution Control Facility provides recycled water to an adjacent power plant and four adjacent golf courses. The Bonanza Mojave Water Resource Center is capable of providing approximately 1,120 acre-feet per year of recycled water to an adjacent park and golf course. The Northwest Water Resource Center will ultimately be capable of providing more than 11,200 acre-feet per year of recycled water for use at golf courses, schools and parks. Total reuse for the City of Las Vegas is about 5,500 acre-feet per year.
The Clark County Water Reclamation District (CCWRD) provides recycled water to power plants, golf courses and parks from the Water Pollution Control Facility. The Desert Breeze Water Resource Center currently treats up to 5 million-gallons per day (MGD) of recycled water. The facility can be expanded to 10 MGD, which is equivalent to 11,200 acre-feet per year of recycled water for use at golf courses, schools and parks.
In addition, Clark County requires new golf courses and nearby landscape areas to use recycled water when applicable. Total CCWRD reuse is approximately 12,000 acre-feet per year.
The city has a water reclamation facility capable of treating 32 MGD of wastewater. Customers currently utilizing recycled water for irrigation include nine golf courses, highway landscaping and a mortuary. Total recycled water is about 8,300 acre-feet per year.
The City of North Las Vegas currently receives wastewater treatment through an agreement with the City of Las Vegas.
Return flow credits
The apportionment of all of the states' Colorado River water is consumptive use (net) allocations. This means that Southern Nevada can actually use more water than its allocation of Colorado River water, as long as we return water back to the river. These return flows are referred to as "return-flow credits."
Return flow credits expand the Southern Nevada Water Authority's Colorado River allocation by approximately 75 percent.
Returning water to the Colorado River
When you take a shower or wash your car at a commercial facility, the unused water flows into the sewer system. This sewer water travels to a wastewater treatment facility, where it is treated.
The highly-treated wastewater is returned to the Colorado River via the Las Vegas Wash, which flows into Lake Mead. The water returned to the lake earns us return-flow credits, which can be used to draw more water than our 300,000 acre-foot apportionment.
By treating Colorado River water after it is used and returning it to the lake, Southern Nevada is able to extend its Colorado River resources. For every gallon of treated Colorado River water returned to the Colorado River, Southern Nevada can withdraw and use an additional gallon beyond Nevada's base allocation.
Conservation and consumptive use
Because water that is used or "wasted" indoors flows into the sanitary sewer, it has an opportunity to be treated and used again. It has not been "consumed" but recycled, and gives us an opportunity for return-flow credits.
Water that is used and/or wasted outdoors evaporates and cannot be used again. This is "consumptive use" as the water was consumed and cannot be reused.