About Trust Your Tap

Iowa Trust Your Tap was created by the Center for Health Effects of Environmental Contaminants (CHEEC) at the University of Iowa to help Iowan's view information about the quality of their drinking water.

At this time, we are only providing water quality information for Public Water Systems (PWSs) that serve communities.

If you get your water from a private well, please visit the Iowa Well Forecasting System or the Iowa DNR Private Well Tracking System to view water quality information available for your well.

Please contact us if you run in to issues using the site.

Frequently Asked Questions

Where does the data come from?

All data on this site are provided by the Iowa Department of Natural Resources and the United States Environmental Protection Agency, and represent sampling results provided by regulated PWSs in Iowa as part of their compliance reporting under the Safe Drinking Water Act (SDWA).

How frequently is the data updated?

Data is updated annually for all regulated PWSs in Iowa in coordination with the Iowa DNR.

Why do some systems have more data than others?
The number of available data points will vary from one PWS to the next depending on their monitoring and reporting requirements under the SDWA.

How do I understand the test results?

When looking at the test results for a specific contaminant, you will see the results plotted over time. You can hover over a specific test result to view the date and contaminant level recorded. Multiple tests from the same day with the same contaminant level will appear as a single point on the graph—hovering over that point will show many tests it represents.

Abnormally high test results may not be initially visible, but can be viewed by adjusting the y-axis slider next to the graph.

Where appropriate, the federally enforceable Maximum Contaminant Level (MCL) is provided as a red, dashed horizontal line. The full list of federally enforceable standards established through the SDWA can be found on the EPA website.

Does a value over the limit (MCL) necessarily mean a violation?

While in most cases a value exceeding the MCL represents a violation, this is not always the case for some contaminants.

Lead and copper, in particular, require that more than 10% of the samples be over the EPA action level in a given period of time to result in a violation. Other examples include certain disinfection byproducts (e.g., total trihalomethanes and haloacetic acids), for which compliance with the MCL is based on a running annual average of values measured for these contaminants.

What does a non-detect value mean?

Most water quality tests have a detection limit—the minimum amount of a contaminant that must be present for it to show up on the test.

A non-detect indicates that the amount of contaminant in the test sample was below the test’s detection limit. While we show non-detect values as 0 on the Y-axis, it does not necessarily mean that level of contaminant is zero.

What do I do if I notice irregularities in the data?

Please contact us at cheec@uiowa.edu.

What if I can’t find my system?

Please contact us at cheec@uiowa.edu.


The University of Iowa and the Center for Health Effects of Environmental Contaminants makes no warranties or guarantees, either expressed or implied, as to the completeness, accuracy or correctness of the data portrayed in this product. Nor do the University of Iowa and the Center for Health Effects of Environmental Contaminants accept any liability arising from any incorrect, incomplete or misleading information contained therein. All information, data and, functionality are provided on an "as is" and "as available" basis.