By Maura Allaire
Ensuring safe water supply for communities across the U.S. represents an emerging challenge. Aging infrastructure, impaired source water and strained community finances can increase the vulnerability of water systems to quality violations. In the aftermath of Flint and other water crises, there is a great need to assess the current state of U.S. drinking water quality.
Recent revelations of non-compliant water quality have captured national attention. And they raise questions. How widespread are violations? And which types of communities and systems are most vulnerable?
Researchers at the Columbia Water Center have addressed these issues by analyzing trends in drinking water quality violations, as part of America’s Water, a National Science Foundation-funded project. This is the first national assessment of trends in drinking water quality violations across several decades. A critical lesson from this study is that water quality violations extend well beyond the problem of lead in Flint’s drinking water.
In 2015, when the Flint water crisis first received national attention, there were nearly 38,000 health-related violations of the Safe Drinking Water Act that affected as many as 15 million people. Also, bacterial and nutrient pollutants were found to be, overwhelmingly, the most prevalent over the past three decades. Yet, these pollutants have not yet received anywhere near the level of public attention as lead contamination.
Contaminants such as total coliform and nitrate result in impairment of source water, elevated risk of water-borne illness, and a seasonal dead zone in the Gulf of Mexico. Aging infrastructure can compound the problem, as demonstrated by Corpus Christi, Texas, a coastal city that is home to nearly 300,000 residents. The city has gone through three boil water advisories this year, causing disruptions for businesses and daily activities. The cause is low levels of chlorine disinfectant in the distribution system, which can elevate the risk of bacterial contamination. Aging and decayed pipes cause water flow to be reduced to part of the system, which adds to the problem.
Last summer, harmful algal blooms shut down the public water supply for more than 400,000 customers in Toledo, Ohio. The massive algal blooms, which turned large swathes of Lake Erie green, were mostly attributed to fertilizer runoff.
Runoff of nutrients and manure from agricultural land have been a major water quality concern for some time. Pollution from agriculture likely contributed to impaired water quality in more than 600,000 miles of rivers and streams in the United States.
Public health is threatened and communities face rising water treatment costs. Yet agricultural runoff is mostly exempted from regulation under the federal Clean Water Act. Only specific, “point sources” are restricted in the quantity of pollution they can emit.
Communities are beginning to take matters into their own hands, as demonstrated by revised farming regulations in Ohio after the major algal blooms that shut-down the Toledo water treatment plant for days. And in Iowa, the Des Moines Water Works is suing several upstream counties for discharging large amounts of nitrate from agricultural lands into the Raccoon River, which serves as the source water for half a million people. The water utility is seeking damages to fund the drastically higher treatment costs due to nitrate levels that are two to three times higher than the drinking water limit.
The treatment plant already has one of the world’s largest nitrate removal facilities. However, the aging facility has had to operate for longer periods in more recent years and is due for a replacement, speculated to cost nearly $100 million. The upstream counties, which are the defendants in the suit, counter that there is no evidence that the nitrate pollution is originating from agribusinesses within their borders.
If the water utility wins, it could set a national precedent for enforcement of the Clean Water Act and might undermine the immunity of agricultural nutrient runoff from regulation. The suit is expected to be heard in the Iowa Supreme Court in June 2017.
An intriguing argument is being made by the Des Moines Water Works in order to classify agricultural runoff as a point source for pollution, and therefore subject to regulation under the Clean Water Act. The water works argues that tile drainage systems used by the upstream farms to prevent their fields from flooding should be considered point sources since water is discharged into the river via pipes. Stakes are high in this case, since drainage districts exist across the country and enable agricultural activity.
In Des Moines, the upgrade of treatment facilities would make the water safe to drink. Yet, this alone would not address the root cause of the problem. Ultimately, we all need both adequate food and safe water. A longer-term solution is to identify strategies that protect source water, while ensuring productive farming activity.
Maura Allaire is a postdoctoral research scientist at the Columbia Water Center. She is working on the America’s Water project and with the Nature Conservancy to inform a national plan for water management that can benefit economies, ecosystems and communities.
McDonald, R., Weber, K., Padowski, J., Boucher, T., Shemie, D. (2016). Estimating watershed degradation over the last century and its impact on water-treatment costs for the world’s large cities. PNAS.
Office of Science and Technology Policy (OSTP) (2010). Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health, Scientific Assessment of Hypoxia in U.S. Coastal Waters. Washington, D.C.
U.S. Environmental Protection Agency (U.S. EPA) (2010). Watershed Assessment, Tracking, and Environmental Results: National Summary of State Information. Washington, D.C.