This week, you're deciding which type of water treatment equipment is best to address perchlorate concerns in your home's water supply in Grafton, Ozaukee County.
Reading Certified Laboratory Test Results for Perchlorate
Test Scope and Reporting Levels
Certified laboratory tests measure perchlorate concentrations in micrograms per liter (µg/L). For Grafton Waterworks, government data show no detections above the 4.0 µg/L reporting level in 12 samples taken between 2002 and 2003. This means perchlorate was either not found above that threshold or below the detection limit.
Interpreting the Results
A detection above the reporting level is a measured concentration, not a violation or indication of unsafe water. Tests do not confirm your individual home's water condition. Only a test of your home's water can determine perchlorate presence or concentration there.
Seasonal and Multi-Year Variation in Perchlorate Levels
Monitoring Timeframe
The EPA's Unregulated Contaminant Monitoring Rule sampled perchlorate in Grafton's water system from November 2002 to June 2003. This period captures several months across winter to summer, but no perchlorate was detected above the threshold during this time.
Implications of Variation
Perchlorate levels can vary over time due to environmental factors, but the lack of detection over several months in this groundwater-supplied system suggests stable low levels during that period. More recent or future monitoring would be necessary to identify any new trends.
Long-Term Effects of Untreated Perchlorate
Potential Impact
Perchlorate is a chemical that can interfere with iodine uptake in the thyroid gland. Over many years, untreated perchlorate in drinking water at elevated levels could disrupt thyroid function, which is important for metabolism and growth. The EPA has not established a federal maximum contaminant level for perchlorate in drinking water.
Importance of Monitoring
Because perchlorate is not routinely regulated at the federal level, monitoring your own water if you rely on private groundwater sources is important to assess whether treatment is needed over time.
How Source Characteristics Affect Perchlorate Expectations
Groundwater Supply Considerations
Grafton’s water comes from groundwater, typically less exposed to some surface pollutants. However, perchlorate can enter groundwater from industrial or agricultural sources. Depth and location of a well impact potential perchlorate presence.
Depth and Testing
Private wells with shallow depths may be more susceptible to perchlorate intrusion. Knowing your well’s depth and location relative to known contamination sources helps determine need for testing.
What to Note Before Choosing Treatment
Essential Information
- Your water source type and well depth (if private).
- Recent certified lab test results for perchlorate in your home water.
- Reports or data from local water authorities about perchlorate in your area.
- Any health advisories or updates from local public health agencies.
Purpose of This Information
This data informs whether perchlorate treatment equipment should be considered and which technology aligns with your water’s condition and household needs.
Choosing treatment requires knowing your water’s perchlorate levels through testing and understanding local public water system records. The Autotrol Perchlorate Filter system ships ready to configure and offers a documented approach for reducing perchlorate if testing shows it is present in your household water.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2003-06-24. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR1 monitoring (2001-2005) for GRAFTON WATERWORKS (WI2460111), WI: 12 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level