Wildlife & Human Health Concerns
The artificial snow made at the Snowbowl Ski Resort is 100% wastewater, reclaimed from Flagstaff’s sewage system. Although the reclaimed sewage water used to make snow at the Arizona Snowbowl Ski Resort is classified as “A+” water, this can be misleading when it comes to human ingestion. The A+ classification is for non-potable water only. Non-potable water is defined by the Arizona Department of Environmental Quality as “any water supply that does not meet federal and state safe drinking standards and is legally barred from human consumption.” Therefore, the artificial snow is not safe for ingestion - either through the mouth, skin, or inhalation (e.g. breathing in snow flakes produced by snow blowers).
More than Urine and Feces: The Chemical Pollutants in Snowbowl’s Fake Snow
There are many chemical pollutants that are not currently filtered out of Flagstaff wastewater which make it into the artificial snow used for snowmaking at the Arizona Snowbowl. In a recently published study, researchers (Yazzie et. al 2026) compared natural snow to the snow made by Arizona Snowbowl. Statistical tests showed a significant difference between the two types of snow for drug-related chemicals and metals. Nineteen medications and drug byproducts showed up at meaningfully higher levels in the Snowbowl’s wastewater snow, including things like an allergy medication, heart/blood-pressure drugs, seizure/mood-stabilizing drugs, and an antibiotic. These chemicals come from medications people take, which end up in wastewater after being excreted from the body. In addition, the researchers found nine metals and minerals were elevated in the heavily-wastewater-based snow, including sodium, potassium, iron, zinc, arsenic, and barium.
Wastewater Pollution Impairs Development of Hormonal/Reproductive Systems
Other studies have showed that pollutants in reclaimed wastewater negatively impact wildlife, causing estrogenic endocrine disruption, hyperthyroidism, disrupted hormone-axis genes, reproductive impairment. A scientific study published in 2015 (Wolff et. al 2015), showed that estrogen and estrogen-like chemicals found in some detergents, plastics, and industrial cleaners, negatively impacted tadpoles living within the Snowbowl’s runoff area. In particular, these pollutants impaired the genes involved in the development of the gonads (sexual organs) in male frogs, leading to a higher proportion of female frogs compared to natural populations outside of the runoff area. Similarly, a study published in 2023 (Zhao et. al 2023) found that zebrafish exposed to reclaimed wastewater caused reproductive impairment, estrogen-like endocrine disruption, and induced hyperthyroidism. They also found these effects that carried over to the next generation in zebrafish populations.
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Research cited:
Stephanie E. Wolff, Nik Veldhoen, Caren C. Helbing, Claire A. Ramirez, Janae M. Malpas, Catherine R. Propper, Estrogenic environmental contaminants alter the mRNA abundance profiles of genes involved in gonadal differentiation of the American bullfrog, Science of The Total Environment, Volumes 521–522, 2015, Pages 380-387, ISSN 0048-9697, https://www.sciencedirect.com/science/article/pii/S0048969715001692.
Fei Zhao, Yinfei Hao, Qianru Xu, Zhineng Hao, Xinhui Li, Lihua Cheng, Dong Chen, Xueqing Shi, Yihua Xiao, Penghao Wei, Xuejun Bi, Safety assessment of organic micropollutants in reclaimed water: Chemical analyses, ecological risk assessments, and in vivo endocrine-disrupting studies, Science of The Total Environment, Volume 884, 2023, 163865, ISSN 0048-9697, https://www.sciencedirect.com/science/article/abs/pii/S0048969723024865
Ecological Concerns
Two scientific reports raise ecological concerns about using treated wastewater to make snow on the San Francisco Peaks. Specifically, they point to changes in the soil and plants due to pollution in the runoff from the artificial snow made from wastewater.
The first study (Stewart 2021) argues that the Peak’s unique alpine ecosystem has had about 1,000 years to settle into a stable balance with very low nutrient levels. Dumping large amounts of nutrient-rich wastewater onto the Peaks, he argues, could throw that balance off in ways that are hard to predict and hard to undo. Stewart uses real-world examples like Florida's Indian River Lagoon, where too many nutrients caused a collapse that killed over 1,000 manatees. Using models, Stewart calculated the levels of two nutrients (nitrogen and phosphorous) in Flagstaff reclaimed wastewater used in snowmaking. He predicted that nitrogen levels in the immediate area of the Snowbowl could rise by 25–52%, and phosphorus by over 700%. These levels raise a concern about wildfire because extra nutrients may cause plants to grow faster than the ecosystem can naturally break them down, leaving more dead plant material lying around as fuel, which could make wildfires more likely. Stewart also notes this excess plant buildup could make the area more prone to erosion.
A second study (Hereford et. al 2022) based on actual field measurements, backs up Stewart’s concerns up with real-world evidence. It found nutrient levels in the soil running off below the Snowbowl resort into Hart Prairie were as much as 10 times higher than natural levels. He traced the extra nutrients back to the snowmaking water rather than other possible sources, such as septic tanks. Researchers also documented actual polluted runoff escaping the resort's boundary onto Hart Prairie during storms in 2021 and 2022, in one case with phosphorus levels 500 times higher than what's normally allowed to flow into a lake or stream.
In summary, Stewart predicted, through modeling, that reclaimed wastewater snowmaking could dangerously destabilize the Peaks' nutrient-poor ecosystem and raise wildfire and erosion risks. Hereford's field measurements later confirmed these concerns, documenting nutrient levels up to 10 times natural background and polluted runoff repeatedly escaping onto Hart Prairie during 2021–2022 storms.
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Research cited:
Threat to Religious Freedom
For decades, Indigenous tribes have argued that commercialized recreation, particularly skiing, is a desecration of the Peaks as a sacred site. They have taken this argument to the United States court system through a series of cases. Looking at the pattern across these cases reveals something troubling: each time, the courts found a real and substantial threat to Indigenous belief systems and religious practices. However, in each case, a legal technicality was used to deny their arguments and any protection of their rights, even while often acknowledging the harm was real. Here is a summary of those cases:
Wilson v. Block (1983): The Hopi Tribe, Navajo Medicine Men's Association, and others argued that an expansion plan further allowing the development of the Snowbowl violated their First Amendment religious freedom rights. The court admitted the project would cause real spiritual harm, but ruled against the tribes anyway because U.S. religious freedom law is built around personal belief, not location-based sacred practices.
Navajo Nation v. U.S. Forest Service (2005–2009): The Navajo Nation and twelve other tribes argued that snowmaking with treated sewage violated the Religious Freedom Restoration Act. An appeals panel initially ruled in the tribes' favor, but the full Ninth Circuit reversed, deciding that since the government wasn't forcing tribes to violate their own beliefs — just doing something offensive on its own land — there was no legal violation. The Supreme Court declined to hear an appeal.
Hopi Tribe v. Arizona Snowbowl (2010–2018): The Hopi Tribe sued Flagstaff in state court, arguing the wastewater use was a public nuisance. The Arizona Supreme Court agreed a nuisance existed, but regardless ruled the Hopi Tribe hadn't suffered a "special injury" distinct enough to sue over it.
These rulings explicitly deny Indigenous religious rights and taken together the pattern shows a legal system with no real framework for protecting sacred, place-based religious practice.
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Sources:
Michael D. McNally. Defend the Sacred: Native American Religious Freedom Beyond the First Amendment. Princeton, NJ: Princeton University Press, 2020.
Kristen A. Carpenter, Living the Sacred: Indigenous Peoples and Religious Freedom, 134 Harv. L. Rev. 2103 (2021), https://harvardlawreview.org/print/vol-134/living-the-sacred-indigenous-peoples-and-religious-freedom/.