Understanding Tannins in Cumberland County Water and Residential Solutions

WSP Whole House Tannin Filter - Yellow Tea-Colored

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1. How Many Samples and Wells Stand Behind the Figures, and What a Small Sample Means

The Portland Water District-Greater system (ME0091300) serves over 135,000 people in Cumberland County, including Cape Elizabeth, Falmouth, Gorham, Portland, Raymond, Scarborough, South Portland, Standish, Westbrook, and Windham. This public water system uses surface water sources and maintains routine monitoring for various water quality factors. However, no federal or system-specific tannin sampling data exists in EPA or related public datasets for this water system, which means there is no direct regional measurement of tannin levels from government sampling. For households, this lack of systemic tannin data means that any tannin-related issue must be confirmed by individual water testing rather than relying on regional figures.

2. How the Constituent Enters Groundwater or the Distribution System in This Region

Tannins are naturally occurring organic compounds typically found in surface waters rich in decaying vegetation, such as lakes, rivers, and reservoirs. The Portland Water District-Greater system sources its supply from surface water, where tannins can enter through natural runoff and organic matter decomposition. While the water system’s routine treatment and multiple process steps address general organic content, specific tannin concentrations are not measured nor reported in the system’s public records. If tannins are present in household water, they originate primarily from the water source rather than distribution or plumbing materials.

3. What Changes for a Large Household, a Second Home, or a Seasonal Property

Households with higher water usage may experience tannin-related effects differently simply due to volume. Seasonal or secondary properties in Cumberland County may face tannin presence that fluctuates with local environmental changes, such as leaf fall or storm runoff, which impact surface water organic levels. For such properties, intermittent or reduced water use can also affect the water quality inside the plumbing system and influence the perceived severity of tannin-related discoloration or staining. Testing water quality during peak and off-peak usage is advisable to capture these variations.

4. A Worked Example: Reading the Record's Median and Range as a Homeowner Would

Since federal or system data does not include tannin figures, homeowners cannot refer to official median or range values for tannins in Cumberland County. Instead, they may review the Portland Water District's public water system record, which shows no health-based violations and lead levels well below regulatory concern. These results provide confidence in overall water safety but do not address tannin presence, which is an aesthetic or secondary quality issue. Homeowners suspecting tannin effects should conduct a dedicated tannin test through certified laboratories to quantify the tannin content and its impact on water appearance.

5. How Sample Depth, Well Depth or Source Type Changes What a Reader Should Expect

The Portland Water District-Greater system relies on surface water, which is a typical source where tannins may occur, unlike groundwater sources where tannin concentrations tend to be lower or absent. For households using private wells or different local water sources in the area, tannin presence and concentration can differ due to well depth or aquifer characteristics. Generally, deeper wells are less likely to have tannins, while shallow wells near organic-rich soils might show more tannin content. Therefore, individual testing based on source type and well characteristics is essential to properly understand tannin presence at the household level.

What You Should NOT Conclude from Area Data

Area-wide water quality figures from the Portland Water District-Greater system confirm there are no health-related violations and that lead levels are low, which does not indicate that tannins are present or absent in any specific home’s water. The absence of system-wide tannin data means that tannin presence cannot be assumed from the general water supply quality report. To confirm if tannins affect your household water, a direct and specific water test for tannins is necessary. If tannins are confirmed and prior treatment equipment has failed, the C-Series Yellow, Tea-Colored Tannin Water Filter offers a documented method to address tannin discoloration and improve water clarity, shipping ready to configure for residential use.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2023-12-31. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA SDWIS record for PORTLAND WATER DISTRICT-GREATER (ME0091300), surface water supply, serving 135068 people: 0 health-based violations of 6 total; lead 90th percentile 0.0019 mg/L