LAS VEGAS (KLAS) — Approximately 40 million people rely on the Colorado River for water, 5% of them, or 2 million are in Nevada. However, the state gets only 1.8% of the river’s water.

How did this happen? In 1922, Nevada signed onto the Colorado River Compact.

It divided the river between the upper basin (part of Arizona, Colorado, New Mexico, Utah and Wyoming) and the lower basin (the rest of Arizona, California, Nevada, and New Mexico).

Based on that agreement, more than 20 years later, those states divvied up how much water they’d get between them.

“Now Southern Nevada was allotted 300,000-acre feet of water. It was the smallest slice of the Colorado River,” said Bronson Mack, who is the outreach manager for the Southern Nevada Water Authority.

Nevada getting the least, while more than half of the water goes to two states: California and Colorado.

“There really wasn’t any expectation that we would have the community here today at that time,” Mack added. “So the Colorado River really was divided up based on agriculture. As far as moving forward for those allocations, it’s really a matter of the seven states developing new agreements that provide flexibility in how we use water, how we share water on the river.”

A federal water shortage was declared in August.

In a “60 Minutes” interview that aired in October, Colorado State University climate scientist Brad Udall said laws governing the Colorado River need to be revisited.

“In some ways a little microcosm, right, of this whole law of the river with these systems that have been put in place that just don’t work. They can’t work. And that’s why a rethink’s needed,” Udall said.

In the meantime, the Southern Nevada Water Authority is urging residents to conserve water, as Lake Mead levels are at a record low.

“You have to keep in mind if the Colorado River was divvied up or re-apportioned, that would ultimately mean some states would lose water, some states may gain water, and ultimately, the expectation is that would land in decades of litigation,” Mack said.

One question viewers have asked about is why does Nevada continue to build in the Las Vegas valley if there is such a critical water shortage?

The I-Team asked Mack about this, and he pointed out that people keep relocating here and they need housing.

He also pointed out that new builds are required to have water-smart landscaping and the water used inside homes gets treated and reused.