Las Vegas has complete toilet-to-tap water. Indoor water is reclaimed, cleaned up, then filtered through various wetlands. 150 millions gallons of water a day come through the Las Vegas Wash, next to the Clark County Wetlands Park, on its way to Lake Las Vegas and then Lake Mead, where it will be reused over and over. 85% of water coming down this wash has already been reclaimed at least once. Wetlands help clean the water further, as does Lake Las Vegas.
During a flash flood in 1999, 4.5 billion gallons came down the wash in 24 hours. That’s why the wash is so wide. It’s meant to handle massive, not-infrequent desert floods.
Rubble from torn-down casinos has been used to line the channel in Wetlands Park.