Water Source and Delivery in Hennepin County’s 112GSSG Aquifer
The 112GSSG aquifer in Hennepin County supplies groundwater that commonly feeds residential wells. Water travels from this shallow aquifer—typically between 9 and 29 feet deep—through subsurface flows before reaching household taps. Understanding the aquifer’s chemical profile provides context for what might occur in tap water, but individual well tests remain essential.
Stepwise Checks: Ruling Out Causes Before Laboratory Testing
Begin by inspecting the household water system for obvious issues unrelated to arsenic, such as plumbing materials or water discoloration from iron or other minerals. If arsenic concerns persist, obtaining certified laboratory testing of your own well water is the only way to confirm actual arsenic levels present on site.
Comparing Hennepin County’s Arsenic Record with Neighboring Areas
The U.S. Geological Survey’s data shows consistent arsenic detection across 23 samples from 20 wells in the aquifer, with values ranging from 0.18 to 19.3 micrograms per liter (µg/L) and a median of 1.0 µg/L. Importantly, no measurements exceeded federal thresholds for arsenic in public drinking water. Neighboring counties may have different sampling results due to geology or well depth differences, so comparisons should be cautious and not assumed to reflect your well’s condition.
Which Household Fixtures Are Likely to Show Effects First
Arsenic presence is generally colorless and odorless, so it does not cause immediate aesthetic issues at fixtures or appliances. However, since arsenic is a dissolved contaminant, it is present throughout the water supply and affects all outlets equally. Unlike minerals causing stains or taste changes, arsenic’s effects are not readily visible. Treatment systems configured to remove arsenic treat the whole household supply to prevent any exposure.
Evaluating Treatment Capacity Relative to Household Water Usage
When considering an arsenic filtration solution, estimate your household’s daily water use—including drinking, cooking, bathing, and appliances—to assess system sizing. Filtration units are designed to meet typical residential demands and maintain contaminant reduction performance without limiting water flow. Choosing a system suited to your volume helps sustain efficiency and reduces maintenance frequency.
Understanding Detected, Median, and Range in Arsenic Sampling Data
In the USGS data, “detected” means arsenic was measured above the minimum reporting limit in all 23 samples. The “median” of 1.0 µg/L represents the middle value across these samples, indicating typical concentrations. The “range” from 0.18 to 19.3 µg/L shows variability among wells. None of these values surpass the federal maximum contaminant level (MCL) of 10 µg/L, which is the health-based standard for arsenic in public water supplies.
Worked Example: Interpreting Arsenic Levels as a Homeowner
Suppose a homeowner reviews this USGS record. With a median of 1.0 µg/L, most wells showed low arsenic levels, but some approached or exceeded the 10 µg/L MCL, up to 19.3 µg/L. Since no sample in this data set exceeded federal limits, the area’s groundwater typically remains within safety guidelines. However, individual wells may differ, so relying solely on area data is insufficient for safety decisions.
Recommended Next Step: Confirm Your Well’s Arsenic Level
To determine arsenic in your household water, order a certified laboratory test specifically for arsenic on a current sample from your tap. This test will provide an accurate measurement for your well, confirming whether treatment is needed. If arsenic is found at concentrations of concern, products like the Fleck Arsenic Filter ship ready to configure and can reduce arsenic reliably for residential use.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2016-09-08. These figures describe groundwater sampled in this area. They are not a test of any individual private well - only a test of that well can establish its own water.
On record: U.S. Geological Survey sampling of Arsenic in the 112GSSG aquifer (Hennepin County): 23 results from 20 wells, median 1.0 ug/L, range 0.18-19.3 ug/L; none above any federal threshold
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