City Cast

What You Should Know About Las Vegas Storm Drains

Scott Dickensheets
Scott Dickensheets
Posted on September 6
Photo of water gurgling down a storm drain.

Storm water makes its way to Lake Mead — untreated. (kerkla/Getty)

In light of this weekend’s heavy rainfall, here are a few words about the valley’s storm drain system.

Two Ways to the Lake

Las Vegas has two systems for disposing of excess water. The sewage system carries sink and toilet water to a treatment plant, where it’s processed before being sent to Lake Mead. Rain and runoff water travels through storm drains and channels directly to the Las Vegas Wash and on to the lake.

Which Means …

Runoff water isn’t treated before it’s dumped back into our main source of drinking water. Therefore, flood control officials say, “The largest source of stormwater pollution in Las Vegas Valley results from everyday activities.” That is, pet waste, pool chemicals, automotive drippings, pesticides, and more. “One quart of motor oil can contaminate over 250,000 gallons of water.” Most of us don’t pour a quart of motor oil into the gutter, of course. On the other hand, oil from driveway leaks gets carried off by rain, and adds up. Tips for preventing your share of that pollution.


Despite the footage of rampaging floodwaters in Las Vegas during the past weekend’s storms, Las Vegas is generally well-protected from flooding — the result of $2 billion in flood-control infrastructure installed by the Regional Flood control District over the last 30 years: some 100 water retention basins and more than 600 miles of flood channels.


There are, notoriously, people living in the valley’s extensive storm tunnel system — about 1,500 of them, according to Shine a Light, a nonprofit that helps such people transition out of the tunnels. (And sometimes helps rescue them after torrential rains.) There’s even been a book about them, as well as a sequel.

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