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The quality — not just quantity — of Arizona's water is a concern. And the list of threats is long

The KJZZ series "Every Last Drop" tackles big questions about Arizona's water future — including what Arizonans can do to make a difference and what’s being done to keep the state's water safe.

Published: May 15, 2023

A creek on the Mogollon Rim. Arizona's water faces a number of potential threats, which can be cleaned up before it comes out of the tap. Ron Dungan/KJZZ

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When every last drop counts, water quality matters more than ever. But some of the state’s leading industries, such as mining and agriculture, along with the byproducts of everyday life, throw off pollutants that can wind up in our aquifers.

It’s a long list, and it includes acid mine drainage, or AMD; fertilizers and pesticides; industrial chemicals; bacteria; perchlorate; mercury; E. coli; metals; arsenic; phosphorus and nitrogen; organic pollution; hydrocarbons; oil spills; gasoline; uranium and lead contamination.

These are the things we know about, and the list keeps growing, said Leif Abrell, who studies emerging contaminants at the University of Arizona.

“There are millions of chemicals that are potentially contaminating our environment, and there are more chemicals being invented, or synthesized every day,” Abrell said.

In other words, we can’t measure everything. In some cases, we don’t even know what to measure for. Adding just one chemical to the list is a long process that begins with a trail of academic papers that eventually lead to regulation. The process can take decades.

“I don’t see a way that we will ever catch up with trying to regulate all the chemicals that probably should be regulated,” Abrell said. “The vast majority of chemicals that I think about, that I’m concerned about, are not regulated.”

Government agencies occasionally add new compounds to the list, but it takes time. And money.


“There’s just no way to financially accomplish that goal. I’m not saying that we shouldn’t try, there are ways to work towards it. But it’s a pretty formidable task,” Abrell said.

Rhett Larson, a water law professor at Arizona State University, says that mining waste is high on the list of pollutants that we know about.

“It is a common problem to have abandoned mining operations that continue to discharge, just because of runoff you know, every time it rains it continues to leach contaminants out of those abandoned tailings,” Larson said.

About five decades ago, Congress passed the Clean Water Act, which guides state and federal agencies that oversee water quality.

“But like any legislation, it’s not perfect,” he said.

Loopholes and a lack of funding can work against the agencies that must carry out the law.

“I mean its stated goal was to eliminate water contamination, and it is a long way away from having achieved that goal,” Larson said.

The good news is just about anything that can get into the water can be removed.

A spring in northern Arizona. Ron Dungan/KJZZ

“This is really a matter of treatment, and money,” Larson said. “Which is to say the technology exists to turn the dirtiest water you can possibly imagine into the cleanest water you could hope for. The question is, do you have enough money to do it?

In urban areas, that cost can be distributed among many users. In rural areas, fewer people bear the cost. Those areas can also rely heavily on groundwater.

Sandy Bahr of the Sierra Club would like to see the Arizona Department of Environmental Quality do a better job of keeping pollutants out before they have to be removed.

“It’s always cheaper to prevent pollution than to try to clean it up,” Bahr said.

A lot of the state’s biggest challenges are in rural communities, some of which are economically disadvantaged and rely exclusively on groundwater. Yet they account for the vast majority of water systems in the state. So far, we’ve been talking about things that can get into the water supply. That doesn’t mean you’re drinking them.

“We make sure that when they pull water out of the ground or take it from surface water, that it is treated to the appropriate drinking water standards,” said Trevor Baggiore, Water Quality Division director for the Arizona Department of Environmental Quality.

ADEQ frequently clashes with environmental groups over permitting, and, in 2021, the Arizona Auditor General's Office issued a report that said it needs to do a better job of groundwater monitoring and other duties. But it does monitor aquifers all over the state, and the agency takes an active role in monitoring water treatment systems, which means that it’s proactive where it counts.

“More than 99% of Arizonans are being served water that meets all safe drinking-water standards.” Baggiore said.

A spring in Tonto National Forest. Ron Dungan/KJZZ

So, while Arizona’s water supply has a lot of potential problems, what comes out of the tap is probably safe to drink.

But as Arizona learns to juggle a growing population with a shrinking water supply, it will also face a growing number of contaminants, such as PFAs, the so-called forever chemicals. Which means maintaining water quality will be more important, and more challenging, than ever.

Explore all the stories in KJZZ's 'Every Last Drop' series

Arizona's water supply is shrinking, but its population is growing. Is it sustainable?

Groundwater is critical to rural Arizona — but there's a struggle to regulate it

Is drought in Arizona and the Southwest the new normal?

To better understand Arizona's water supply, we retrace its origins

How much can at-home conservation impact Arizona's water shortage?

How Scottsdale's drought plan has reduced the city's water footprint

Gray water’s untapped potential is clouded by complexity

As drought worsens, will Arizonans see higher water bills?

Ron Dungan was a senior field correspondent at KJZZ from 2020 to 2024.