LAS VEGAS (KLAS) — Sweeping powers to limit residential water use are part of legislation introduced last week in Carson City.

As Lake Mead continues to shrink and the ominous “bathtub ring” just gets bigger, the Southern Nevada Water Authority (SNWA) could get the authority to limit how much water residents can use. It’s one of many powers proposed under Assembly Bill 220 (AB220).

The formal legalese in the bottom half of the 2,723-word “digest” of AB220 says:

“Section 27 of this bill authorizes the Board of Directors of the Authority to restrict the use of water by a single-family residence to not more than 0.5 acre-feet of water during any year in which a shortage on the Colorado River has been declared by the Federal Government.”

The federal government formally declared a water shortage in August 2021, so if the bill becomes law, the effect would be immediate.

The shoreline changes as water recedes at Lake Mead in this photo from early February, 2023. (Duncan Phenix / 8NewsNow)

The loose measurement of 0.5 acre-feet of water translates literally to 162,925.5 gallons — well above the average usage of homes here. The Las Vegas Valley Water District in 2018 said the average home uses just over 100,000 gallons a year. An acre-foot has been described generally as enough water for two to three homes for a year. That’s a description used around the country, and not specific to the desert climate of Southern Nevada.

AB220 also formally establishes a new power for SNWA’s general manager: the authority to restrict water usage during certain water emergencies and shortages. SNWA’s board of directors would review the decision before it goes into place.

The bill is clearly aimed at giving SNWA the power to shut off the water to some of the valley’s biggest users. But who are they?

In 2021, 8 News Now revealed the Top 100 residential water users in the valley, including a home in Spanish Gate owned by the Prince of Brunei that used more than 12 million gallons. Two other homes used more than 10 million gallons.

When the story aired, Bronson Mack with the Las Vegas Valley Water District said 20% of customers use about 40% of water.

See the list of top residential water users here:

Another report detailed the Top 15 water users — both commercial and residential — in Las Vegas, Henderson and North Las Vegas. Find that breakdown here:

But there’s much more in AB220 that puts teeth into the message of conservation.

Section 31 of the bill outright prohibits the use of Colorado River water for irrigating nonfunctional turf on any parcel of property that is not used exclusively as a single-family residence. Many of SNWA’s conservation efforts have been directed at accomplishing this over the past few years.

And while it might not appear on the surface to have anything to do with water conservation, the bill requires any property owner with a septic tank within 400 feet of existing sewer lines to get connected to the sewer system by Jan. 1, 2054. Water that travels through the sewers is reclaimed as it is processed on its way to Lake Mead. Septic systems remove water from the system completely. It could be an expensive proposition for any property owner, as AB220 removes language that says the property owner can’t be charged more than $200.

The bill also requires use of irrigation controllers and sprinklers that have been certified under the WaterSense program.

AB220 also revises existing state law about “connecting a well to a municipal water system.” Instead, it will provide money to pay some costs for plugging and abandoning a well, and connecting the property to a municipal water system “under certain circumstances.”

The bill’s sponsor is listed as the Assembly Committee on Natural Resources. It was introduced on Feb. 23.