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Southern Nevada Water Authority

Return Flow Credits

Return Flow Credits

Highly-treated wastewater is returned to the Colorado River via
the Las Vegas Wash.

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.

Return flow credits expand the Southern Nevada Water Authority's Colorado River supply 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 sanitary sewer. 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 above our 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 "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.