How Tannins Enter Groundwater or the Distribution System in This Region
Tannins are naturally occurring organic compounds released when vegetation—such as leaves, bark, and roots—decomposes in soil and surface waters. In areas like Monroe, Union County, where the public water system primarily relies on surface water sources, tannins can be introduced when runoff carries organic materials into reservoirs or rivers feeding the water system. These compounds can impart a yellow or tea-like color to the water and may affect its aesthetic qualities, including taste and staining potential.
A Worked Example: Reading the Record’s Median and Range as a Homeowner Would
While government data for the Union County Water System do not include tannin measurements, understanding typical sampling practices can help residents interpret water quality reports. For example, the public system’s record shows two health-based violations among seven total, but none related to tannins. The median and range of sampled constituents, such as lead levels, provide insights into what is typical for this water source; however, tannins are not routinely tracked by federal monitoring. This means one cannot find official median or range values for tannins from the system’s water quality reporting.
What 'Detected', 'Median', and 'Range' Mean in the Sampling Record on This Page
When a water constituent is "detected," it means a measurement instrument has identified its presence in the water sample. Detection alone does not indicate a safety or regulatory violation—especially for constituents like tannins, which are not subject to federal health standards. The "median" refers to the middle value in a set of test results, providing a sense of typical concentration, while the "range" shows the lowest and highest concentrations observed during monitoring. Since tannins are not monitored in this system, no such statistical summary exists for them in government records.
How Seasonal or Multi-Year Variation Shows in the Record (Dates and Ranges Given)
Water quality in surface-sourced systems like Union County’s can fluctuate seasonally due to changes in rainfall, vegetation cycles, and runoff patterns. Although tannins are not measured here, their levels in water generally rise during times of heavy leaf fall or after storms that wash organic matter into reservoirs. The public water system’s record reflects a monitoring period extending up to the end of 2025, where variations in other constituents have been documented, demonstrating how water quality can vary year to year, and seasonally, even if tannins themselves remain unmeasured.
What a Certified Laboratory Test for This Constituent Reports and How to Read It
To know if tannins affect your household water, independent laboratory testing is necessary. Such tests quantify tannin concentrations and sometimes report other related parameters like color and organic content. Test reports typically provide numerical values indicating how much tannin is present, which homeowners can compare against secondary aesthetic standards or consult with treatment specialists. Understanding these results helps identify if tannins contribute to discoloration or staining issues in your home.
To address tannin concerns documented through laboratory testing, specialized equipment designed to reduce tea-colored tannins—such as the C-Series Yellow, Tea-Colored Tannin Water Filter—ships ready to configure for home use. This system targets tannins effectively, improving water clarity and reducing staining potential.
The government’s public water system data cover the entire Union County Water System serving Monroe and surrounding areas, describing system-wide conditions but not individual household water quality. For detailed data, visit the EPA’s official water system records.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2025-12-31. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA SDWIS record for UNION COUNTY WATER SYSTEM (NC0190413), surface water supply, serving 169685 people: 2 health-based violations of 7 total; lead 90th percentile 0 mg/L