New research is a wake-up call for water safety in private wells

Is your drinking water safe? That’s the question Economics Professor Gabriel Lade urged rural Iowans with private wells to think about. As lead researcher in a study published last month in Environmental Science & Technology, Dr. Lade surveyed 22,000 rural households—a scale rarely seen in research like this. Supported by the U.S. Department of Agriculture, the study showed that with just a little information and some simple nitrate test strips, more people started testing their water. The results showed they were even willing to pay for these tools. 

Professor Lade sheds light on the broader public health concerns related to drinking water contamination and offers an economist’s perspective on weighing the costs and benefits of environmental policies.

How many Americans rely on private wells for their drinking water?

Around 23 million U.S. households rely on private wells. The federal government provides basic information about what contaminants to be concerned about, and some states provide free or subsidized testing as well as information. But these households are entirely responsible for ensuring the quality of their drinking water.

The only way to know if your water is safe is to send samples to a lab to test the water. However, prior research has shown that testing mostly occurs when a well is dug or when a house is sold, despite federal guidance recommending testing for certain contaminants at least annually.

Why did you opt to focus on Iowa?

Agriculture is one of the largest contributors to surface and ground water pollution across the U.S. due to excess nutrients being applied to crops. This problem is especially large in Iowa, which is one of the most agriculturally intensive areas of the world. Iowa has a lot of both row crop and animal agriculture, which produces some of the highest amounts of nutrients of any U.S. state, so if it’s going to be a big problem anywhere, it’s going to be a big problem in rural Iowa. 

Previous research showed that Iowa’s state program offering free well-water testing was underutilized, with counties spending only a fraction of their allocated funds. We saw an opportunity to boost participation in a program that people should be fully utilizing.

You surveyed nearly 22,000 rural households and received a 50% response rate. That’s quite high. What does that tell you? 

First, it tells us that we designed the survey well. We followed best practices, keeping the survey simple, and even included $2 bills in our mailers to boost response rates. But this response rate was high even with those efforts, which suggests we piqued people’s interest. The toughest part of mail surveys is getting people to open them since most mail is junk these days.

When people saw it was from a trusted source like Iowa State University Extension, and then noticed the topic, it likely made them think, “Oh yeah, I haven’t thought about whether my well water is safe for a few years at least.” It was a very simple survey, emphasizing “This is really important for your health and the state’s health. We want to learn more about what you’re doing to ensure your family is safe.” A lot of people responded.

As far as barriers for testing water quality, people might not have known the program existed. Maybe the test strips showed some pink and they realized, “I might have a nitrate issue.” It could also be behavioral; people often procrastinate on tasks like this until reminded. It’s probably a mix of informational and behavioral barriers, helping people overcome the tendency of putting off important tasks.

Your study found that nearly 40% of households don’t test their water frequently, don’t filter it, and don’t supplement their drinking water with other sources, which means exposure to pollution may be high. What are the potential health effects of this exposure? 

The most well-known consequence of drinking water with high nitrate concentrations is that it inhibits your blood cells’ ability to carry oxygen. While this isn’t a major issue for adults, it can be deadly for babies. The first case of what’s called “blue baby syndrome” was documented in rural Iowa in the early 20th century. When babies were fed formula made with well water containing really high nitrate concentrations, oxygen deprivation started to kick in. The baby would turn blue because their body couldn’t process the amount of oxygen they needed.

That’s the most famous case, but blue baby syndrome hasn’t been documented in the U.S. in a long time. A lot of public health research has shifted towards understanding the impacts of consuming moderate to low amounts of nitrate over long periods. This research is notoriously difficult because it’s hard to link long-term exposure to low nitrate concentrations directly to health impacts that might arise decades later. However, growing evidence shows that long-term exposure to water with higher levels of nitrates is associated with increased incidences of bladder and colorectal cancer, thyroid disease, and neural tube defects in newborns.

What are some of the societal costs to this lack of testing? 

While some households might not experience any human health costs if they spend money to filter their water or use bottled water, those expenditures are costs, too. If we clean up groundwater and reduce nutrient levels, these households wouldn’t have to spend as much on filtration or bottled water.

However, we found that people weren’t doing as much as they should to avoid exposure to contaminated drinking water, which suggests that the health costs — whether private or societal (through Medicare and Medicaid)—could be higher than previously thought. While we don’t have direct evidence of these costs yet, the data strongly suggest that the health costs might be significant, given that people aren’t taking enough precautionary measures to avoid contaminated well water.

What’s the bottom line lesson from this study? 

It raises concerns about rural households and their drinking water quality. This subset of the population doesn’t get much attention unless the problem is very acute, like a massive spill or a terrible pollutant entering the groundwater. But many of these households have contaminants in their drinking water that could be concerning, especially with long-term exposure.

Our findings show that few people in our large sample avoid exposure or even know whether their water is safe. Water can look clear, smell fine, and taste fine but still contain contaminants that aren’t good for your health. This suggests a need for more programs and outreach to encourage rural households to change their behaviors — to test their water more, filter it more, or maybe even avoid it.  

While we invest heavily in public water systems, it may be worthwhile to redirect some of these funds toward subsidizing rural households to get their water tested. In many states, testing is a hassle and expensive. There’s a lot of low-hanging fruit here — just informing households about whether their well water is safe and whether they should be doing something about it can be effective. 

This seems like an environmental issue, but you’re an economist. What draws you to this issue?

As economists, we often weigh the costs and benefits of environmental policies. Typically, the costs are easy to quantify. We can easily calculate the cost of taking land out of agricultural production or installing a filtration system. Industries are very good at making sure we know what those costs are. However, the benefits, especially health-related ones, are harder to measure. That’s what this research program is starting to explore — quantifying how many people are potentially exposed, understanding their baseline behaviors, and trying to measure how much they’re spending to avoid drinking contaminated water. This helps us make better policy decisions when comparing different programs that can reduce pollutants.

From here, what are some next steps? What is still unknown? 

I’d love to see this type of work expanded to other states to see if similar behaviors, like low-testing rates and minimal use of filtration or bottled water, are common. We’re also seeking funding to continue this research in Iowa. 

One challenge we faced was determining if testing water quality led to changes in other behaviors, like using bottled water or installing filters. Our sample size wasn’t large enough to find strong evidence of that. We need to learn more about the impacts of these interventions and how to improve them. More importantly, we need to expand this research and nudge policymakers to consider programs that lower the barriers to testing water quality for households with wells.