Based on the amount of time it takes a drop of water to travel from its source, through the Mint Farm aquifer and to the City's wellfield, a boundary was created to define the limits of the aquifer and establish an area for wellhead protection.
As part of its Wellhead Protection Program, the City collects groundwater samples from deep sentinel wells surrounding the Mint Farm wellfield every six months to look for changes in water quality. In addition to compliance sampling required by the Department of Health, the production wells are also sampled annually as part of wellhead protection. View summary reports and laboratory results from past sampling events in the Archive Center.
The most current sampling event occurred in May of 2019 but no report has been finalized yet.
The City uses a live data engine to compile and analyze the data contained in the semi-annual Water Quality Reports. This allows the data to be trended and visually displayed such that large volumes of data can be more easily monitored and interpreted. Copies of the complete workbooks for each of the wells can be downloaded below:
An example of the dashboard look used for analysis.
Other Analytic Documents
Wellhead Protection Sampling Analyte List (PDF) - A complete list of the analytes tested for as part of wellhead protection sampling including health based screening levels. To define the risk to human health if an analyte is detected at a concentration which exceeds the screening level, a "criticality value" has been assigned to each analyte based on carcinogenicity, mutagenicity, and reproductive effects, as well as overall toxicity.
Monitoring Well Sampling Program (PDF) - A list of routine Department of Health test panels and special interest analytes originally recommended for semi-annual sampling events including recommended testing frequency, Environmental Protection Agency test method and estimated laboratory costs.