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Digging Into an Issue: Water Quality Indicators for a Thriving Natural World

Updated: Apr 4

To fully assess community well-being, one must look at a broad range of indicators, and one can quickly find themselves out of their depth. That’s where IP3 steps in—we curate the most meaningful indicators for use on IP3 ASSESS, our web-based data solution designed and built for changemakers using data to advance equitable well-being in communities around the Nation. With our extensive knowledge of and experience with community indicators we help clients dig into the issues and measure what matters.

Digging into Water Quality

Recently, the IP3 data team got knee-deep (pun intended) into water quality data. Virtually all water consumed in the U.S. comes from fresh surface waters and groundwater aquifers, and despite the fact that U.S. tap water is among the safest in the world, it can be contaminated by chemicals, microbes, and radionuclides. Drinking water with unsafe levels of contaminants can cause negative health effects like gastrointestinal illness, nervous system and reproductive effects, and chronic diseases like cancer. Poor water quality also disproportionately affects communities of color, and rural and low-income communities. It’s important to understand water quality issues in a community, but sifting through water quality data can get complicated.

Due to data compatibility issues, we recently sought to replace the Drinking Water Violations indicator on IP3 ASSESS from County Health Rankings with something new (you can still find that data on CHR&R’s website). We started by exploring data available from EPA’s Safe Drinking Water Information System (SDWIS), the source of the CHR&R data, and that’s where things got complicated. Despite making a significant amount of program data available, using SDWIS data presented a challenge, as the unit of analysis is facility, and data are available for a staggering 650 toxic chemicals. IP3 ASSESS requires data aggregated to the Census tract or county level, and uses only the most meaningful indicators of water quality to include in the Vital Conditions for Health and Well-Being framework.

As we evaluated the data landscape, we kept the following questions in mind: 

  • What data are being used by peers in the field? What can we learn from their experiences?

  • How relevant is the data with regard to health and well-being?

  • How are the data collected and analyzed?

  • Are data from a reputable source?

  • How recent are the data? How frequent are the updates?

  • What geographic levels are available? Are there any gaps in geographic availability?

Data to Consider

After careful review, three indicators (Disinfectant Biproducts - Total Trihalomethanes, Disinfectant Biproducts - Haloacetic, and Nitrates) were selected to incorporate into the Vital Conditions data framework. These indicators represent some of the most common community water system violations and some of the most serious water quality issues communities face today. Adding these measures into the framework has strengthened our measurement of the Vital Conditions and achieved a balance of environmental indicators represented by the framework.

We found that the National Environmental Public Health Tracking Network—a trusted source of environmental health data at the county and tract levels—makes multiple indicators related to drinking water accessible online! We dug into the cited literature, and key findings are presented below.

Disinfection By Products (DBP): Trihalomethane, Haloacetic

How does the contaminant impact human health? DBPs show toxic and carcinogenic effects in lab studies and are associated with bladder and colorectal cancer. There is some evidence that DBPs are associated with adverse pregnancy outcomes. 

What are sources and exposures? DBPs are formed when disinfectants used to inactivate microbial contaminants in water react with other materials that are present (primarily organic matter). The highest concentrations of DBP are found in water derived from surface sources. Geologic circumstances and salt water intrusion in coastal areas can affect DBP levels. 

What do the data show? Data will indicate places where water supply systems may benefit from enhancement of source water quality, infrastructure improvements, or other interventions to reduce DBP exposure.


How does the contaminant impact human health? Arsenic is a known carcinogen that has been associated with lung, bladder, liver and skin cancers. It is also associated with other adverse health effects, including nausea, cardiovascular disease, developmental and reproductive effects, Diabetes Mellitus, and skin keratosis and hyperpigmentation.

What are sources and exposures? Arsenic in drinking water can come from elevated levels of arsenic in soil and ground water from application and runoff of arsenical pesticides and leachate from coal ash and landfills; however, the primary sources are geologic formations from which arsenic can be dissolved. Higher concentrations of arsenic are found in groundwater, although arsenic compounds are found in both ground and surface waters. Exposure to arsenic from drinking water is very low for most community water systems.

What do the data show? Although the potential for adverse health effects from drinking water exposure to arsenic is very low for most municipal drinking water systems, the data will provide insight about the distribution of potential arsenic exposure levels for populations served by community water supplies.


How does the contaminant impact human health? Nitrate exposure is associated with “Blue baby” syndrome, and adverse reproductive outcomes such as spontaneous abortions, intrauterine growth retardation, and various birth defects. Long-term exposure is a risk factor for cancer and has been associated with cancers at multiple sites.

What are sources and exposures? Nitrate is the most commonly found contaminant in groundwater aquifers worldwide, and anthropogenic sources of nitrates are increasing. Surface water and shallow wells in rural and urban areas can be affected by nitrate contamination, which originates from nitrate-containing fertilizers, sewage and septic tanks, and decaying natural material such as animal waste.

What do the data show? Data will indicate places where water supply systems may benefit from enhancement of source water quality, infrastructure improvements or other interventions to reduce nitrate exposure.

Through our research into water quality data, we learned about the opportunities and challenges of working with the dataset—lessons we'll incorporate into how we handle these data on IP3 ASSESS. For example, not all states report water quality data; it is not available in the national dataset, and we are beginning to work with interested clients from states without available data.

Where community assessment gets tricky, IP3 is here to help. If you’re interested in more robust support around identifying, accessing, and using community health data in your work, contact us today to learn more!

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