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Jun 22, 2023

Where does your drinking water come from?

The Gazette researched where Iowans get their water, how it is or isn’t treated,

The Gazette researched where Iowans get their water, how it is or isn't treated, and threats to the vital resource.

Mar. 19, 2023 5:00 am, Updated: Mar. 20, 2023 9:36 am

Drinking water is harvested from the earth, the sky, the seas. We worry about having enough of it and how to keep it clean, spending millions on infrastructure.

But how do Iowans get their drinking water?

It can spurt from several sources across the state: deep wells that dip into aquifers, shallow wells stationed near waterways, and surface water from rivers, lakes and reservoirs. Residents can get their hands on some through one of the state's 1,800-plus public water supply systems. Or, they may be one of the approximately 250,000 Iowans who depend on private wells.

The groundwater that feeds private wells can be contaminated by farm runoff that is often unmeasured and unregulated. Deeper private wells have their own challenges with minerals, including arsenic and lead. And, although municipal water supplies are tightly regulated, suppliers must use expensive technology to combat contaminants — some of which have been emerging more in recent years.

To kick off the Iowa Ideas in-depth week about drinking water, The Gazette researched where Iowans’ water comes from, how it is or isn't treated, and potential threats to the vital resource. We reviewed the complex journey a droplet takes from source to faucet and obstacles it may face along the way.

Iowa Ideas is hosting a free, virtual In-Depth Week series called Water Quality March 20-24. It's an exploration of what Iowa has — and hasn't — done to protect its vital resource.

The week features five sessions, held 12-1 p.m. each day. Full session descriptions, including a list of panelists, and registration can be found at iowaideas.com. Here is the week's schedule:

• Monday: Water Quality Policy Overview

• Tuesday: Private Wells

• Wednesday: Iowa's Nutrient Reduction Strategy turns 10

• Thursday: Emerging Contaminants

• Friday: Keeping the water flowing: How do cities troubleshoot water challenges?

"Regardless of where you go to grab a gallon of water — a puddle somewhere, go to the river, go to a well — that gallon of water is going to be made up of whatever's there," said Cedar Rapids utilities director Roy Hesemann. "First and foremost, you have to figure out what you've got — what you're dealing with — and then figure out how you want to treat it."

When it comes to public water supplies, treatment processes differ depending on factors like the water source, the location of facilities and the resources available to purchase and maintain infrastructure.

Cedar Rapids, for instance, gets its drinking water from 52 shallow wells stationed along the Cedar River that suck up groundwater percolating through the riverbed. About 36 million gallons of water is drawn each day on average.

From there, it's pumped to the city's two drinking water treatment plants, where physical and chemical mechanisms transform it into drinkable water.

Some steps remove elements from the liquid. For instance, when it first enters the plants, it is aerated to release any gases in the droplets. It's also softened using lime to remove calcium, magnesium and other contributors to water hardness. Ultraviolet reactors zap and disfigure viruses into incompetence.

Other steps add substances to the water. Sometimes, extra ammonia is put in toward the beginning of the treatment process. It will combine with added chlorine in a later step to create a disinfectant for the water. Fluoride is added to promote dental health, and zinc orthophosphate is added to minimize pipe corrosion.

What leaves the plant and is sent to around 130,000 people is safe drinking water — heavily regulated by federal standards, as with all public water supplies. Any problem with the water requires a public notification to customers.

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"We touch everybody's life in the city every day, and I personally want to make sure that we are providing the highest quality level of public health that we possibly can," Hesemann said.

Des Moines Water Works, another large water supplier in the state, draws water both directly from the surface and from shallow wells around the Des Moines and Raccoon Rivers. For the most part, its treatment process is similar to Cedar Rapids’ — complete with lime softening, filtration and additions of fluoride and chlorine.

But, since Des Moines Water Works draws from surface water at two of its three plants, it has extra steps for additional threats. Activated carbon is added to absorb and filter out organic materials like pesticides and insecticides. Sediment is settled out of the water. And, most notably, the supplier has a nitrate removal facility.

"We have a lot of challenges," said Ted Corrigan, CEO and general manager of Des Moines Water Works. "But, because we are using river water, we have to have a very robust process. It removes pretty much everything."

Although among the largest public water suppliers in the state, Cedar Rapids and Des Moines are in the minority by drawing their source water directly from or around rivers. Nearly 92 percent of state suppliers — serving 54 percent of the population — pump groundwater instead, generally to less populated areas.

Water treatment infrastructure can look different for those smaller towns.

Marion, for instance, has a decentralized simpler process, where groundwater from deep aquifers is disinfected with chlorine gas at four main wells sites before getting pumped to customers. Flow from certain wells run through a new iron removal plant that cost $2.8 million.

Infrastructure with that price tag may be cost-prohibitive for communities with fewer resources and personnel, though.

Mount Vernon's five wells dip into the Jordan and Silurian-Devonian aquifers to provide water for the city's population of around 4,500. Chlorine and phosphate are added as disinfectant and corrosion protection. With the city's budget, any future infrastructure updates would be an uphill battle.

"I think it all comes down to money," said city water and wastewater superintendent Alex Volkov. "It's never easy to find money for something that generally people don't see … Things that are buried underground, as long as it does OK, generally people don't feel like spending millions of dollars on it."

When you picture a well, do you envision an opening wide enough to drop down a bucket, complete with a handle to haul your water into reach? Think again.

Unlike the old-fashioned stereotype, 90 percent of drinking water wells are only 4 to 6 inches wide, said Chad Greiner of Greiner Well & Pump in Keota. For five generations, the company has been hooking up pumps in residential wells.

By definition, private wells are ones that serve no more than 25 people at least 60 days a year. They are not regulated under the Safe Drinking Water Act, so owners are responsible for their upkeep and monitoring.

Most wells are lined with PVC and include periodic openings covered with screens that allow in groundwater. That water is then pumped into pipes that deliver it to sinks and showers in homes.

Residential wells can be as shallow as 100 feet or more than 1,000 feet deep, depending on the geology of the earth and the depth of the source aquifer.

"In the Cedar Rapids area, the wells are definitely going deeper than they used to," Greiner said. "You keep building houses next to each other and everyone running lawn sprinklers, you’re doing to deplete the aquifer. You have to go down deeper and deeper to get the same amount of water."

An estimated 7.6 percent of Iowans get their drinking water from private wells, which is about half the estimated 14 percent to 15 percent across the country, according to Kelsey Pieper, assistant professor of civil and environmental engineering at Northeastern University in Boston.

The bulk of people using private wells for drinking water live in suburban developments on the periphery of metropolitan areas.

"In rural areas, you’ll have a greater share of the population supplied by wells, but sheer number of users are on fringe area of urban centers," Pieper said. "When you have urban growth, city water lines are not keeping up."

Palo and Hills moved from private wells to public water systems in the last 15 years. Swisher residents, who now rely mostly on private wells, voted down a $19.2 million public water system earlier this month.

Growing up, most kids are taught that the iconic H2O compound is what flows through our waterways, homes and communities. But that's the pure form of water — not the kind we encounter on a day-to-day basis.

"Water has a lot of baggage that it carries. Whether it surface water or groundwater, it picks up things as it moves," like gases, minerals and contaminants, Hesemann said. "Water is a very complex compound."

Aside from relatively harmless baggage, like magnesium and calcium, water can pick up harmful contaminants. Public water supplies and private wells face some of the same pollutants in their source waters, including excess nutrients levels that typically spike in the spring and fall when farmers apply fertilizer to fields.

Nitrate pollution has plagued suppliers like Des Moines Water Works since the 1980s. Its nitrate removal facility was commissioned in 1992, and other features have been added since, like storage ponds that allow nitrate to settle before treatment.

"We've done a lot of things to try to stay ahead of this since 1992, but we're still battling it," Corrigan said. "But the really disturbing part of that whole thing is that nitrate is really kind of just the tip of the iceberg of this nutrient problem."

Des Moines Water Works now battles algal blooms that feed on excess nutrients and can create dangerous toxins, which the treatment process is not currently designed to remove. For now, the supplier is avoiding pulling water from areas with blooms, Corrigan said.

Since Cedar Rapids draws from shallow wells beneath the Cedar River, its water quality is more consistent, Hesemann said. As the water percolates through the riverbed to the wells, the sand and gravel help purify it.

An emerging concern for public water supplies and private wells is per- and polyfluorinated substances — or PFAS — which are human-made "forever chemicals" that build up and persist over time. Last week, the U.S. Environmental Protection Agency released long-awaited limits for the chemicals in drinking water.

They have been found at potentially-dangerous levels in some private wells in Linn County but are not believed to be a widespread problem for most wells. To gauge PFAS contamination in public water supplies, the Iowa Department of Natural Resources has sampled treated drinking water for at least 130 public water suppliers to date.

The source of pollutants isn't always clear. Bacteria is found in feces from birds and other wildlife, but it can also come from manure runoff from animal confinements. Lead in drinking water often comes from eroding pipes, but also is found in the Earth's crust. PFAS can be found in common products like non-stick cookware, water-resistant clothes, cleaning supplies, food packaging and adhesives.

The growing list of potential pollutants is why testing is important. Public water suppliers are required to routinely test their source water and finished drinking water. But for keeping private well water clean, the burden rests on the owners. A survey of more than 21,000 private well owners in 14 Iowa counties in 2018 and 2019 showed only about 10 percent tested their water quality in the past year.

The Grants to Counties Program — often underutilized — provides money to counties to help residents pay for well testing, which is recommended at least once a year.

Counties can use the money to plug abandoned wells, rehabilitate damaged wells and monitor well water. Testing for any substance with a federal standard — like PFAS or algal bloom toxins — can also be reimbursed. Some funds can help subsidize costs for other well-related needs.

If your private well test results come back high for one or more contaminants, the next steps are to consider how to best remove the contaminant: Do you need to remove it just from drinking water, or from all water used in the house?

"When we’re talking about lead, you can just do something at the kitchen tap," said Kelsey Pieper, assistant professor of civil and environmental engineering at Northeastern University in Boston. "You can get options from $10 to up to a couple hundred bucks."

High levels of iron in well water, on the other hand, not only taste bad but can ruin your laundry, she said. That means you might need to treat all the water in your house. "Now you’re talking about treatment in the thousands. It's really house-specific and based on what people want and how much they want to spend."

Homeowners can better protect their well water by:

• Making sure the well casing extends at least a foot above the ground with a cap that seals tightly to prevent contamination.

• Remove any standing water around the well.

• Look for any cracks or damages to the well.

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