This week, you need to decide how to address copper stains appearing in your household fixtures and surfaces. Knowing what the local water data says can guide your choices.
1. Write down what you know about your water supply and stain locations
Begin by noting whether your household water source is a private well or connected to a municipal supply. Identify the locations where copper staining is visible—such as sinks, tubs, or dishware—and whether it appears more in hot or cold water. Record any previous water tests you have, including dates and which contaminants were analyzed.
2. Understand the copper sampling terms from Merrimack County aquifer data
The U.S. Geological Survey sampled 62 separate wells in the Merrimack County aquifer between December 2021 and March 2022, with a total of 80 results. Copper was detected in 71 samples, with concentrations ranging from 0.4 to 7000.0 micrograms per liter (ug/L). The median concentration was 6.5 ug/L. Detection means copper was measured at a certain level; it does not imply any regulatory violation or safety issue.
None of these samples exceeded federal health-based limits for copper. This means, based on this regional sampling, copper levels in the aquifer are generally within ranges considered acceptable for water quality standards.
3. Identify where copper stains typically first appear in the home and why
Copper stains often show on fixtures that frequently come into contact with water, such as bathroom sinks, kitchen faucets, and bathtubs. Copper can deposit as bluish-green or turquoise stains when water containing dissolved copper ions reacts with air and surfaces. Hot water appliances like dishwashers or water heaters may accelerate staining due to higher temperatures encouraging copper release from pipes or fittings.
4. Know the difference between aesthetic secondary standards and health-based limits for copper
Aesthetic secondary standards concern how copper affects water taste, odor, color, and staining, not safety. While copper levels above certain thresholds might lead to discoloration or staining, levels below those thresholds are not necessarily free of any staining effect. Health-based limits established by federal agencies aim to protect against adverse health effects, and regional samples from Merrimack County did not exceed those limits, indicating no documented health risk from copper in the area aquifer water.
5. Observe how sampling dates and copper ranges show seasonal or multi-year variation
The Merrimack County aquifer sampling occurred over several months spanning winter into early spring (December 2021 to March 2022). Concentrations ranged widely, from very low (0.4 ug/L) to relatively high levels (7000.0 ug/L) in some wells. This range may reflect factors such as local geology, well depth, or seasonal effects like groundwater flow changes. Recognizing that copper levels can fluctuate over time is important when considering treatment options.
To resolve how much copper is in your home’s water and whether it is causing your staining, order a water test specifically measuring copper concentration from your water source. A result indicating copper above typical aesthetic thresholds would confirm copper’s role in the stains. If staining is a concern, the Fleck Blue-Green Copper Stains Filter ships ready to configure and is designed to reduce copper in household water, helping manage and prevent copper staining on fixtures and surfaces.
Where this information comes from
Source: USGS groundwater sampling. Sampled 2022-03-30. 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 Copper in the aquifer (Merrimack County): 80 results from 62 wells, median 6.5 ug/L, range 0.4-7000.0 ug/L; none above any federal threshold