The majority of Americans are provided high-quality drinking water. About 90% of people in the United States get their water from a Public Water System. The U.S. Environmental Protection Agency (EPA) sets regulations for treating and monitoring drinking water delivered by public water systems. Drinking water protection programs at the state and national levels play a critical role in ensuring high-quality drinking water and in protecting the public's health.
The Tracking Network has data and information about the levels of several contaminants that can be found in drinking water. These contaminants were selected for the Tracking Network because they occur more frequently in drinking water at levels that may be of public health significance.
Public water systems in the United States provide drinking water that is among the highest quality in the world. However, drinking water contains some contaminants at low levels and can become contaminated at higher levels of pollutants.
Drinking water quality is an important public health issue because contamination in a single system can expose many people at once. People can be exposed to contaminants in drinking water by
drinking the water
eating foods prepared with the water
breathing water droplets or chemicals released from the water while showering
absorbing chemicals through their skin while washing
The majority of community water systems meet all health-based water quality standards. Therefore, the risk of disease from drinking water supplied by a community water system is low.
However, exposure to contaminants in drinking water can cause many adverse effects, some of which can be immediate with symptoms occurring soon after drinking the water. An example is gastrointestinal illness. Other effects can develop over time, such as reproductive disorders, cancer or neurological disorders.
Please view individual contaminant data pages for more specific health information.
Tracking Public Drinking Water Quality involves collecting data about the levels of 10 select contaminants that are tested for in public drinking water supplies according to the Safe Drinking Water Act.
This page provides general information about drinking water quality data and measures developed by the Iowa Public Health Tracking program. Contact us for more information about these data.
The annual mean (average) and maximum concentrations of arsenic, atrazine, di(2-ethylhexyl) phthalate (DEHP), disinfection byproducts (DBP), nitrates, radium, tetrachloroethene (PCE), trichloroethene (TCE) and uranium for community water systems in Iowa.
If the concentrations of arsenic, atrazine, DEHP, DBP’s, nitrates, radium, PCE, TCE and uranium are increasing or decreasing over time.
The data provide summary information on arsenic, atrazine, di(2-ethylhexyl) phthalate (DEHP), disinfection byproducts (DBPs), nitrates, radium, tetrachloroethene (PCE), tricloroethene (TCE) and uranium concentrations in drinking water from community water systems.
These data can be used to determine the potential for public health impacts from contaminant levels of concern. However, they are not gathered specifically to assess the level of exposure or to track changes in water quality over time.
State and local partners can use the data for program planning and evaluation.
Several measures use comparisons to commonly used benchmarks, such as the Maximum Contaminant Level (MCL). MCLs are developed to account for possible health risks, as well as how practical it is to treat water so that the contaminant concentration is lowered.
The sources of contaminants in drinking water.
The levels of arsenic, atrazine, di(2-ethylhexyl) phthalate (DEHP), disinfection byproducts (DBPs), nitrates, radium, tetrachloroethene (PCE), tricloroethene (TCE) and uranium, in individual community water systems.
Information about water quality in water sources other than community water systems and private wells.
These data are not gathered specifically to assess the level of exposure or to track changes in water quality over time, they can be used to determine the potential for public health impacts from contaminant levels of concern.
The Safe Drinking Water Information System (SDWIS) which is maintained by the Water Supply Operations program at the Iowa Department of Natural Resources.
EPA requires community water systems to provide drinking water that meets standards established under the Safe Drinking Water Act.
The Iowa Public Health Tracking portal displays public drinking water data from the year 2000 through the most recent year of data available.
These are the contaminants that the Center for Disease Control's National Environmental Public Health Tracking Network selected, because they appear more often in drinking water at levels that may be of public health significance.
Sample results with concentrations less than the detection limit have been replaced with a value equal to 1/2 the detection limit for the analytical method used when calculating average concentrations.
If all sample results during a time period were non-detects no average concentration is calculated and the Public Water System is reported as a "ND."
No sensitivity analyses were conducted to characterize how the approaches to handling non-detects may impact the drinking water quality data; therefore, it is possible that the analysis may produce biased estimates of the mean—especially if a large proportion of samples are below the limit of detection for the analytical method.
These data are limited to community water systems in Iowa (i.e., systems that serve 15 or more locations or 25 or more people, year-round in Iowa.
Does not include data on unregulated drinking water providers, namely private drinking water wells or very small systems or mutual in which there are less than 15 retail connections and less than 25 year-round residents.
Concentrations in drinking water systems cannot be directly linked to exposures and health risks, because they do not account for water use and consumption practices. In addition, people may obtain drinking water from sources other than community water systems (e.g., private wells, bottled water, workplace, school). Concentrations may not reflect levels in finished drinking water or water at the consumer's tap.
The current form of the data and measures contain one record for each active community water system per year (i.e., active at the time of data analysis). Sampling results from inactive systems that were active prior to data analysis are not included in the data and measures. Early missing values may be because the water system was not yet active, or the system was not required to take a compliance sample during that particular time period. The data set does not distinguish between these two scenarios.
Trends can be difficult to interpret if water quality standards and treatment requirements change over time.
Presenting average concentrations by calendar year is not usually consistent with how maximum contaminant levels (MCLs) established by US Environmental Protection Agency (EPA) are calculated (i.e., typically based on running averages).
The accuracy of the population served information is unknown. Water systems derive population estimates using census estimates, number of water connections, or other means during the year reported.
Systems may receive a sampling waiver from the state for reduced frequency of monitoring based on low analytical results. Reduced monitoring frequencies lead to a reduced number of samples.
