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ST. GEORGE — Various news outlets have outed Utah's Dixie region as the greatest consumer of water anywhere in the country.
Reports from Bloomberg and HBO's "Last Week Tonight with John Oliver" have made the claim, using data calculated by measuring water in gallons per capita per day, a number that has for decades appeared in statewide and federal reports.
St. George uses between nearly 300 and 391 gallons per capita per day, depending on the year and report. This figure is consistently among the highest in the nation.
However, KSL.com interviewed multiple water authorities across the western United States, who confirmed that St. George's gallons per capita per day appear artificially high because of how different communities calculate water usage.
"It's confusing because it sounds like a standard measurement, but it's not. There's not a uniform policy on how GPCD is calculated," said Karry Rathje, communications and government affairs director at the Washington County Water Conservancy District.
"We as an agency at the Southern Nevada Water Authority have always cautioned against using gallons per capita per day to measure water efficiency against other communities," said Bronson Mack, spokesman for the Southern Nevada Water Authority.
Douglas MacEachern, of the Arizona Department of Water Resources, also confirmed that GPCD is not a metric standardized by the federal government and communities have discretion on how to calculate GPCD.
Utah water use looks artificially high
"Some communities didn't count water for golf courses," Mack said of GPCD calculations. "They only counted water for single-family homes — they excluded water for businesses. ... Some of them haven't included irrigation water or water used by farmers."
"For us, here in Las Vegas, we take our total water use that was delivered to our communities — so, how much water we took off of Lake Mead, or out of our groundwater — and then we subtract the amount of water that we return back to Lake Mead because all of our indoor water use goes back to Lake Mead. It's non-consumptive. It just passed through the system and went back to the system. We subtract what we returned back to the system because we didn't consume it, and then divide that by the population served divided by 365 to arrive at our GPCD."
HBO's "Last Week Tonight with John Oliver" pointed to Las Vegas as a model for other places in water conservation, and St. George as a model of what to avoid.
The GPCD for St. George, Utah, is really not comparable with the GPCD in San Francisco. Why? Two completely different climates
–Bronson Mack, Southern Nevada Water Authority
However, water officials in Nevada and Utah cautioned that their conservation efforts are not drastically different.
"Utah is very proactive about trying to compile all of our water use data within municipal public water system boundaries," Rachel Shilton, of the Utah Department of Water Resources, said. "I don't know of any other state in the country that does that other than Utah."
"That 300 gallons per capita per day is a very old number that included all metered water uses in Washington County," Rathje said. "It included potable water, secondary water and reuse water, so that in a lot of cases water was being counted twice — because it was used initially. And then it was treated, and it was used as secondary water for irrigation."
"To my knowledge, Utah is the only state in the nation that applies that double counting process, because they're looking at the overall water use — which is really great information for planning purposes to understand how much a community is actually using," Rathje said. "But a lot of people took that data and misrepresented it as 'this is how much they're using compared to other communities,' which have a different methodology, which created the appearance of excessive use."
Mack confirmed Las Vegas did not have secondary water usage, but Washington County did.
"I think a better method is water consumption," said Zachary Renstrom, general manager at the Washington County Water Conservancy District. "When we use a method that's similar to Las Vegas, those numbers are almost half instantly off the top."
Mack said, "Our journalist friends obviously do see some validity in being able to make these comparisons. It's just that there isn't the nuance on all of the other influences and variables that can shift or change a GPCD number."
Both offices also highlighted Doug Bennett, a longtime leader in Las Vegas' pioneering water conservation, who left the Southern Nevada Water Authority earlier in 2023 to join the Washington County Water Conservatory as water conservation manager.
Climate differences and how to use GCPD measures effectively
"We have always said that gallons per capita per day is a useful measure for communities to measure their own water efficiency against themselves," Mack said.
"Las Vegas has a GPCD goal. We have set a goal as a community to achieve 86 gallons per capita per day by 2035," he continued. "Last year our GPCD was 104. We've come down from 2002 being our peak water use year that we compare ourselves to. We've declined from 211 gallons per person per day down to 104. ... And we already know based on our water use for this calendar year that we will be well below 104."
"In northern Utah, we are looking at trying to drop our water use down to 170 gallons per capita per day," said Shilton. "That includes outdoor water use."
While the discrepancy between gallons per capita per day of 170 and 104 might seem large, officials noted climate and population affect GCPD goals.
"The GPCD for St. George, Utah, is really not comparable with the GPCD in San Francisco. Why? Two completely different climates. ... That variability has an influence on water use," Mack said.
"Water use in Utah that's appropriate would be different than water use back East," Shilton said. She gave the example that comparisons between the eastern United States and Utah would be poor because outdoor water use in the East is minimal due to rainfall — but in arid Utah, it could be necessary for a plant's survival.
"Northern Utah is different from southern Utah, which is one of the reasons that water use in Washington County is high. Their growing season is 11 months, whereas, in the Uintas, it's five months — so it's half of that," Shilton said, cautioning against comparisons even within the state.
"We have done city comparisons between a Utah city with a California city or an Arizona city that is kind of an equivalent population and equivalent area — and the water uses are similar," Shilton concluded. "There is not a lot of variation you would see if you compared St. George to, I don't know, Sacramento."
Washington County Water Conservatory said the Utah Legislature decided — due to confusion about GPCD comparisons — that the state will begin reporting water consumption using state and federal data.
