FLUSHED WITH SUCCESS: Aurora and other Colorado communities push past ‘toilet-to-tap’ reluctancy

When Aurora buys one bucket of water, it’s really buying multiple buckets of water. Each drop of water will likely be used over and over again.

The growing city approaching 400,000 residents isn’t interested so much in acquiring single-use water anymore, said Greg Baker, spokesperson for Aurora Water. With its Prairie Waters potable reuse system, Aurora can recapture and reuse about 95% of the city’s water, so having multiple uses written into water rights agreements has become a top priority as water rights are likened to gold in the West — expensive and often hard to come by.

Aurora’s method — sterilizing wastewater from toilets, sinks and factories and then piping it back into homes and businesses as tap water — is catching on across the U.S.

In the Los Angeles area, plans to recycle wastewater for drinking are moving along with little fanfare just two decades after similar efforts in the city sparked such a backlash they had to be abandoned. The practice, which must meet federal drinking water standards, has been adopted in several places around the country, including nearby Orange County.

“We’ve had a sea change in terms of public attitudes toward wastewater recycling,” said David Nahai, the former general manager of the Los Angeles Department of Water and Power.

The shifting attitudes around a concept once dismissively dubbed “toilet to tap” come as dry regions scramble for ways to increase water supplies as their populations boom and climate change intensifies droughts. Other strategies gaining traction include collecting runoff from streams and roads after storms, and stripping seawater of salt and other minerals, a process that’s still relatively rare and expensive.

Though there are still only about two dozen communities in the U.S. using some form of recycled water for drinking, that number is projected to more than double in the next 15 years, according to WateReuse, a group that helps cities adopt such conservation practices.

In most places that do it, the sterilized water is usually mixed back into a lake, river or other natural source before being reused — a step that helps make the idea of drinking treated sewage go down easier for some. 

In Aurora, the process is thanks to the Prairie Waters system, which was opened in 2010. It starts south of Weld County along the Platte River, where Aurora holds water rights that can be used “to extinction,” meaning nearly endlessly. 

“Essentially, this means that the water residents use for washing, laundry, showering, as well as some of the water from lawn watering, stays in the South Platte River Basin,” Aurora Water explains.

A few dozen wells on the basin pull water through hundreds of feet of sand and gravel to purify the water. Next, the water is pumped into basins of more sand and gravel where filtration continues. Finally, pipes take the water to three different pump stations, which lift the water 1,000 feet over a ridge and back to the Peter D. Binney Purification Facility, near Aurora Reservoir.

From there the water is treated and pumped back out to the city’s thousands of homes and businesses, where the cycle begins all over again. 

“We’ve truly ingrained re-use into our mentality here,” Baker with Aurora Water said. The agency plans to continue adding wells along the project as needs grow. Aurora’s population is expected to double within the next 30 to 40 years.

Currently, the facility treats about 50 million gallons of water each day.

Funding for more wastewater recycling projects is on the way. The bipartisan infrastructure bill passed by Congress has $1 billion for water reuse projects in the West, including the $3.4 billion project in Southern California.

And tucked into the federal budget reconciliation package being debated is $125 million in grants for alternative water sources nationwide that could include reuse technologies.

Plans for expansion of the Aurora Prairie Waters project are ever-evolving and so there isn’t a build out budget attached, Baker said. 

The Southern California project would be the nation’s largest wastewater recycling program, producing enough water to supply 500,000 homes, according to the Metropolitan Water District, which serves 19 million people in Los Angeles and surrounding counties.

In Colorado, over two dozen facilities already recycle water for non-drinking purposes, which is more affordable than cleaning it for drinking — Aurora started its own irrigation program back in the ‘60s. But growing populations mean cities could need to pull additional supply from the Colorado River, which is already strained from overuse.

At that point, it might make sense to start recycling for drinking purposes as well, said Greg Fisher, head of demand planning for Denver Water.

To warm residents to the idea of recycling waste water into drinkable tap water, Colorado Springs Utilities is hosting a mobile exhibit that shows how wastewater recycling works. On a cold, rainy afternoon, dozens of visitors showed up to learn about the carbon-based purification process and sample the results, which several noted tasted no different than their usual supply.

The recycling process typically entails disinfecting wastewater with ozone gas or ultraviolet light to remove viruses and bacteria, then filtering it through membranes with microscopic pores to remove solids and trace contaminants.

Not all water can be recycled locally. Often, Western communities are required to send treated wastewater back to its source, so that it can eventually be used by other places that depend on that same body of water.

“You have to put the water back into the river because it’s not yours,” said Patricia Sinicropi, executive director of WateReuse. 

As a result, much of the country already consumes water that’s been recycled to some degree, simply by living downstream from others. It’s why drinking water undergoes stringent sterilization even when it’s pulled from a river or lake that looks clean.

Encouraged by efforts in other cities, even places with stable water supplies are considering recycling their own wastewater. After a poll showed broad support for the idea in Boise, Idaho, city officials began studying plans to recharge local groundwater with treated wastewater.

“We need to be managing for the potential impacts of climate change,” said Haley Falconer, a senior manager in the city’s environmental division.

That’s why Aurora’s water acquisition efforts have focused on multiple uses. Even the city’s recent purchase of water in the London Mine, located near Alma in Park County, met this criteria.

“This sale provides a large amount of water for a growing municipal entity without diverting tributary water from the basin. As a non-tributary water source, it can be used and reused by Aurora ‘to extinction,’” the city wrote of the $34 million deal, which was completed in 2018. “Reuse increases the water available to meet new demands and reduces the quantity of additional acquisitions.”

The Southern California project, which still needs to undergo environmental review and finalize its funding plan, would also lessen the region’s need to pipe in water from afar. In exchange for financing from water agencies in Nevada and Arizona, the area is ceding some of its share of the Colorado River. 

“We’re taking advantage of a water supply that’s right here in our backyard,” said Deven Upadhyay, chief operating officer for the Metropolitan Water District.

Officials emphasize the project uses technology that’s been used safely elsewhere, including in Israel and Singapore. The reassurances have become critical after a separate Los Angeles wastewater treatment plant, which uses a different process to purify water for irrigation and industrial purposes, flooded and spilled sewage into the ocean in July. 

“The last thing that any of us want is one of these projects that have a water quality hiccup that sets back public perception,” Upadhyay said.

Education was a big part of the Prairie Waters project more than a decade ago. Baker with Aurora Water said without that piece the city could have run into problems like other places, but Aurorans seemed to be receptive to conservation efforts. Like Colorado Springs, Aurora also invited residents to taste test the water. It’s some of the best in the country.

Baker said in the decade Aurora has been running Prairie Waters there hasn’t been one complaint about the quality of the water, and that’s the point.

“The goal is to be indistinguishable from our mountain sources,” he said.

— Managing Editor Kara Mason contributed to this story