Tucson to consider time-of-day watering restrictions due to CAP cuts

Time-of-day watering restrictions, pool size limits, limits on golf course irrigation and requirements for draining pool water into the sewers are all under consideration at Tucson City Hall.

They are among the proposals two City Council members said should be considered to help Tucson close a looming gap between its Central Arizona Project drinking water supply from the Colorado River and people’s demands for it, amid ongoing drought and the city’s plans to leave some CAP water in Lake Mead to slow its decline.

City Manager Michael Ortega listed these and other possible measures in a memo Thursday, the same day Mayor Regina Romero announced the city is preparing to leave 110,000 acre-feet in dwindling Lake Mead through 2025.

Ortega didn’t endorse any of the measures, but said at least some are worth additional study and consideration.

And outside water experts said in interviews they believe these won’t be the last cuts Tucson will face in the next three years as the seven Colorado River Basin states, including Arizona, continue negotiating a much larger package of water use curbs.

“I don’t think anything at this point should be off the table,” said Tucson Councilman Kevin Dahl, who is among the council members pushing most aggressively for tougher water conservation measures as the Colorado River’s situation grows more tenuous.

“We should look at things (like) the expense we spend per gallon conserved. We should look at incentives and prohibitions. Maybe we should have incentives for people to have pool covers (to reduce evaporation),” he said. “We should offer people incentives down the road to fill in pools, or restrict new pools. It’s a jigsaw puzzle we will play with over time.”

Councilman Steve Kozachik said, “Yes, we need a full-court press right now through encouraging more conservation. Some of it may wind up being statutory and be enforced, (although) I certainly would prefer this to be voluntary.”

‘Continue pushing ourselves’

Romero announced the city will leave more than one-third of its CAP drinking water supply in Lake Mead this year to raise the water level of the long-declining reservoir at the Arizona-Nevada border.

By cutting the city’s annual CAP supply this year by 50,000 acre-feet from its normal 144,191 acre-feet, Tucson will, for the first time in years if ever, be using more CAP water than it’s getting.

The city also agreed to leave 30,000 acre-feet a year in the lake in 2024 and 2025, meaning it will still have more CAP supplies than demand in those years. The U.S. Bureau of Reclamation will compensate Tucson for leaving this water behind, although the amount hasn’t been announced yet.

If Tucson has a CAP demand-supply gap this year, it could dip into a reserve of CAP supplies stored underground big enough to last well over 5 years at current consumption rates. Those reserves have grown steadily over the years as Tucson Water was able to recharge far more water into the aquifer than its customers needed at the time. City officials have long pointed to that supply as a potential backstop for when CAP supplies ran short — which everyone has expected to happen.

But Dahl, Kozachik and Romero all agreed Friday the city should try to conserve water first to fill any demand-supply shortfall.

“I know that we’ve been very good stewards in Tucson at conserving our water,” Romero said. “I know for a fact that we have the capacity as Tucsonans to live with less than our (CAP) allocation.

“We have to continue pushing ourselves in terms of conservation. We know we have water resources that we can live with for the next three years. For the first year, we’ll be pushing ourselves. The following two years will be something we can do. I know for a fact that Tucsonans want to make sure we’re doing everything we possibly can. I will knock at their doors. I want to have a conversation with the community. This is something we have to get done,” Romero said.

Kozachik said his preference would be for “the city to get customers to conduct their own water audits, to repair leaky pipes and to get people to stop watering lawns when it’s raining. This is going to be an issue that the community is going to have to get our arms around.

“But I do have confidence in city residents. We’ve been a leader in this. Our water consumption is lower than it was when we had this conversation three decades ago. We’ve done a good job. We need to do a better job,” Kozachik said.

Specifics on the table

Asked for details about specific conservation strategies, Romero said, “The memo is what’s on the table at this point,” plus other proposals already working their way through the council.

The city manager’s memo was prepared in response to suggestions from council members in February to look at possible additional conservation measures.

Measures limiting what times of the day people can water outdoors have already been enacted in some California cities and in Denver, while Las Vegas limits what weekday people can water outdoors — limits that change by the season. Daytime limits on watering reduce evaporation.

Back to homepage

Subscriber Login

Keep reading with a digital access subscription.

Subscribe now

But those cities have far more grassy lawns than Tucson has, which could limit water savings such measures could achieve here, Ortega’s memo said.

“Turf consumes a lot of water, and spray and sprinkler irrigation can be easily reported,” he wrote. City staff is working on remote sensing to determine how much turf exists in the city.

Regarding limiting the size of new swimming pools, he said staff will continue gathering data from city and county development services officials about current trends in pool installation, to provide an estimated impact.

As for requiring people to drain their pool water into the sewers, “the technical feasibility of this measure needs to be evaluated,” Ortega wrote. “Staff will review as resources allow.”

Whatever federal money the city does get for leaving the water in Lake Mead, Romero said, “my intention as the mayor is to make sure we are continuing to invest in water conservation methods and technology for further conservation.”

The city should also consider using that money for cleanup of some of the potentially cancer-causing PFAS compounds known to be in city groundwater supplies, she said.

“We have to continue diversifying our water resources,” Romero said.

The City Council is already working on numerous other conservation measures that are in various stages of the approval process. They include requiring new housing development to employ “green infrastructure” technology such as rainwater harvesting and to install EPA-certified low water use appliances and fixtures.

They also include a measure to first ban new, “non-functional” lawns in business development, later in housing development, and ultimately in existing development. Another measure under consideration would require businesses to pay increasingly higher rates as their water use rises, as city residents already must do.

Also, Dahl in particular is interested in a proposal — not yet fully reviewed by city staff — to require all new housing development to use “net zero” water, meaning they won’t add to the city’s existing water use. That could be done by requiring the developers to pay to install low water use plumbing fixtures in older homes, whose residents couldn’t otherwise afford them, he said.

‘Watching the river run dry’

Dahl and Kozachik also said they believe the 110,000 acre-feet won’t be the only water the city leaves in Lake Mead in the next few years, meaning still more conservation measures may be needed.

That’s because the seven river basin states are negotiating today over a plan to reduce their total water use from the river by 2 million to 4 million acre-feet.

The cuts would be felt across the entire river basin, but particularly in the Lower Basin states of Arizona, California and Nevada, which use far more total water than the Upper Basin states of Colorado, New Mexico, Utah and Wyoming.

“We don’t know” whether Tucson and the Gila River Indian Community, which last week also agreed to leave large amounts of CAP water in the lake, will have to take additional cuts, said Doug MacEachern, an Arizona Department of Water Resources spokesman.

“We don’t know how deep the cuts might be,” and ADWR officials also don’t know what will be coming in a draft environmental report from the Bureau of Reclamation outlining what cuts it will suggest, he said. “Cuts could exceed the volumes in those agreements.”

Tucson’s willingness to save 110,000 acre-feet likely won’t act as a “safe harbor,” shielding the city from any additional cuts when and if they are approved, said Sharon Megdal and Sarah Porter, directors of water research centers at the University of Arizona and Arizona State University, respectively.

“This is just a voluntary conservation measure,” Porter said of the water to be saved by Tucson and the Gila community.

Kozachik said that while extraordinarily heavy snowpack will bring much greater than normal river runoff this year — the eighth highest spring-summer runoff into Lake Powell since 1963 — he’s convinced this year’s bonanza will be temporary as the region’s long-term drought reasserts itself in future years.

“We’re all standing by the side of the Colorado River, claiming our rights, watching the river run dry,” he said.