Pentair 1,4-Dioxane Filter

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Local Water System and How Water Reaches Your Home

The public water system serving parts of New Haven County, including Clinton, Guilford, Madison, Old Saybrook, and Westbrook, draws water from surface water sources. This system provides water to roughly 33,975 people through over 18,000 connections. The water is treated and distributed through a network that delivers it to residential taps across these communities.

Understanding Low-Level Reporting of 1,4-Dioxane

Why are 1,4-dioxane concentrations reported to three decimal places?

Measurements of 1,4-dioxane, also known as the cyclic ether or solvent stabiliser, in this system’s water were reported down to 0.001 micrograms per litre (µg/L, equivalent to parts per billion). This high level of precision reflects analytical methods capable of detecting trace amounts, even when the presence is very low or non-detectable. It does not imply a safety concern but helps document exact quantities found or not found.

What does a 'not detected above the reporting level' result mean?

For all 20 samples taken between February and November 2014 under the EPA’s unregulated contaminant monitoring, no 1,4-dioxane was detected above 0.07 µg/L (0.07 ppb). This measurement indicates that, if present, the concentration did not exceed the threshold necessary for reporting. It is not a violation nor an indication of unsafe water.

Interpreting Reverse Osmosis Treatment Performance Statements

How are reverse osmosis rejection percentages for 1,4-dioxane reported?

Reverse osmosis (RO) membranes can reduce concentrations of various dissolved compounds, including cyclic ethers like 1,4-dioxane. The effectiveness is typically expressed as a percentage of contaminant removed under specific test conditions. However, percentages vary by feed water chemistry, operating parameters, and membrane condition, thus they are not absolute guarantees for any household system.

Why can rejection percentages be misleading if taken as fixed values?

Because actual removal depends on site-specific factors, a published rejection rate should be used as a general guide rather than a promise. Testing your own water before and after treatment is necessary to understand actual performance relative to your supply.

Consequences of Long-Term Untreated 1,4-Dioxane Presence

What does prolonged exposure to low levels of the solvent stabiliser imply?

1,4-Dioxane is a synthetic chemical used industrially and as a solvent stabiliser. While there is no federal maximum contaminant level (MCL), EPA has established a cancer risk reference concentration of 0.35 µg/L. Long-term consumption of water consistently above this benchmark could present health concerns. Available data show this system has no detected levels above 0.07 µg/L, well below the risk-based reference point, implying limited concern for current public water.

What if private wells or alternate sources are used?

Government sampling covers the public water system only. Private well water can vary greatly, and its 1,4-dioxane concentration is unknown without specific laboratory analysis. Testing private sources directly is essential to confirm any presence or risk.

Contextualizing Measured Concentrations with Federal Guidelines

What does the federal cancer risk reference concentration indicate?

The EPA’s cancer risk reference concentration of 0.35 micrograms per litre (ppb) for 1,4-dioxane serves as a scientific estimate of a concentration below which health risks are presumed to be minimal in the long term. The New Haven public water system’s measured values fall below one-fifth of this reference, based on reported results.

What does 'no established federal MCL' mean for consumers?

Because no federal maximum contaminant level exists for 1,4-dioxane, water suppliers are not required to treat to a specific legal limit. Instead, monitoring and voluntary guidelines inform consumers and support risk management decisions.

Interpreting the Sampling Scope and Significance

How many samples support the reported figures?

The data presented come from 20 samples collected over approximately nine months during the EPA’s Unregulated Contaminant Monitoring Rule (UCMR3) from 2013 to 2015. These samples represent the public water system, not individual homes.

What does the limited sample size imply?

A relatively small number of samples provides an overview but cannot capture all potential variations in water quality over time or across all connections. Individual water testing is recommended to fully understand a home’s water condition related to 1,4-dioxane.

Can these results be applied to private well water?

Public water system results do not reflect private well water quality. Wells may be affected by local land use or contamination sources differently and require separate laboratory analysis.

Documented Solution for Home Use

Households seeking to address detected or suspected 1,4-dioxane in their water may consider the Pentair 1,4-Dioxane Filter. This system is designed to treat solvent stabilisers like the cyclic ether effectively and ships ready to configure for residential water treatment needs. Because actual water demand and 1,4-dioxane levels vary, test your water to determine the specific figure to select appropriate capacity and ensure effective treatment.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2014-11-18. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA UCMR3 monitoring (2013-2015) for CT Water Co. - Shoreline R., Guilford S. (CT0608011), CT: 20 results across 1 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level