Pentek Yellow, Tea-Colored Tannin Water Filter

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How Tannins Enter Groundwater or the Distribution System in Fresno

Fresno’s public water system relies on surface water sources, which can naturally contain organic materials like tannins. Tannins are color-causing organic compounds that leach from decaying vegetation and soils into water bodies. Although federal datasets do not monitor tannins specifically for Fresno’s water system, the surface water origin of Fresno’s supply is a common setting for tannins to appear. This type of water can carry tea-colored tinting from these organics before any treatment.

Which Fixtures, Appliances, or Processes Are Affected First and Why

When tannins are present, households often notice changes first at fixtures such as kitchen faucets and sinks because tannins can stain water and surfaces. Tannins also affect hot water appliances and appliances using water for cleaning or rinsing, leading to tea-colored water stains on laundry or bathtubs. This discoloration is a purely aesthetic issue and does not indicate a health hazard. Failure of previous tannin treatment equipment can result in a return of these visual effects in water.

How the Treated Water Differs at the Tap Once the Documented Technology Is in Place

Introducing the Pentek Yellow, Tea-Colored Tannin Water Filter can restore clear water appearance at the tap. This system uses specialized filtration media designed to reduce tannin compounds, eliminating the tea-colored tint and preventing staining on household fixtures and fabrics. Once configured, the household should see a marked difference in water clarity and reduction in tannin-related discoloration without changes to water safety or taste.

What the Measured Range Means Against the Relevant Federal Standard, and What It Does Not Mean

According to EPA records, Fresno’s public water system currently shows no health-based violations. The system’s lead levels in distribution pipes are non-detectable based on recent sampling, further supporting water safety. Because tannins are not regulated by federal health standards, their presence does not constitute a violation or safety concern. Instead, tannins are considered aesthetic and secondary in nature. Detection of tannins or related organics requires targeted testing beyond routine municipal analysis and does not imply hazard or legal noncompliance.

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

Water sourced from surface bodies, such as the Sacramento-San Joaquin River system feeding Fresno, is more likely to carry tannins naturally compared to deep groundwater wells. Sample depth affects test results for organics: shallow samples often show higher tannin levels due to surface runoff and organic decay. Conversely, deeper sources tend to have lower organic content but may carry other mineral profiles. Knowing whether water comes from surface or groundwater is essential to understanding the potential for tannin occurrence.

Next Steps: Testing to Confirm and Resolve Your Water Condition

To confirm the presence and concentration of tannins in your household water after your previous equipment failure, the most reliable step is to order a certified laboratory test specifically for tannins or color-causing organics. This test will clarify whether tannins are causing discoloration in your water and at what levels. Once confirmed, using the Pentek Yellow, Tea-Colored Tannin Water Filter can effectively reduce these compounds and restore water clarity throughout your household.

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 CITY OF FRESNO (CA1010007), surface water supply, serving 545716 people: 0 health-based violations of 1 total; lead 90th percentile 0 mg/L