Pentair 1,4-Dioxane Filter

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You may notice common water uses in your Indianapolis home—such as showering, cooking, or filling the humidifier—seem unaffected in obvious ways, but understanding 1,4-dioxane presence in water requires specific clarity beyond taste or smell.

Which fixtures, appliances or processes are affected first and why?

1,4-Dioxane is a synthetic chemical that can be present in surface water sources, including the supply for Indianapolis Water serving Marion County. It does not typically cause immediate changes in water color or odor, so the first clues often come from laboratory testing rather than household observation. Appliances that use large volumes of water, like dishwashers, washing machines, or whole-house humidifiers, interact most extensively with the water supply and thus have the highest potential for exposure to 1,4-dioxane. Faucets and showers also contribute but to a lesser degree in terms of volume.

What changes for a large household, a second home, or a seasonal property?

In larger households, the cumulative water usage can increase exposure potential to any substances present, including 1,4-dioxane, although no federal maximum contaminant level (MCL) currently governs this compound. For second homes or seasonal properties, water usage patterns may be intermittent, which can affect water stagnation and quality differently, but detectability of 1,4-dioxane remains reliant on water quality tests rather than usage observations.

The order in which to rule things out, from cheapest check to laboratory test

Begin with confirming general water quality reports available from Indianapolis Water, the public system serving Marion County. These reports show that among 26 samples collected in 2013-2015 under EPA's Unregulated Contaminant Monitoring Rule 3 (UCMR3), 1,4-dioxane was detected 11 times with a highest recorded value of 0.28 µg/L and a median of those detections at 0.17 µg/L. There is no federal MCL for 1,4-dioxane, and no health-based violations are on record for this water system.

Next, homeowners who want to learn their own home's water profile for 1,4-dioxane should request a laboratory test of their specific water supply, as localized plumbing and sources can differ from system-wide values.

How public-system records differ from private-well testing in what they establish

Public water system records, such as those for Indianapolis Water, reflect wide-area sampling and give a broad understanding of water quality trends over time and multiple locations. They do not provide precise information about any individual home’s water. Private wells, if applicable, require individual testing to establish personal water quality. The EPA’s data for the public system show no health-based violations for 1,4-dioxane, but only tests of the actual water from a home’s tap can confirm that home’s condition.

A worked example: reading the record's median and range as a homeowner would

Consider the Indianapolis Water public system record: out of 26 samples, 1,4-dioxane was detected 11 times, with values ranging from just above 0.07 µg/L (the reporting level) up to 0.28 µg/L, and a median detected value of 0.17 µg/L. This means that when 1,4-dioxane appeared in these samples, it was typically around 0.17 µg/L, well below the EPA cancer risk reference concentration of 0.35 µg/L. This data assures that 1,4-dioxane is present sometimes in the water supply at low levels, but it does not reveal what level exists at any particular home’s tap.

What 'detected', 'median' and 'range' mean in the sampling record on this page

• Detected: Indicates that testing instruments measured a concentration of 1,4-dioxane above the reporting limit of 0.07 µg/L in that sample.
• Median: The midpoint value of all detected concentrations, here 0.17 µg/L, meaning half of the detected values were below and half were above this concentration.
• Range: The span between the lowest detected concentration (above 0.07 µg/L) and the highest measured concentration, which was 0.28 µg/L.

These terms describe the sample results but do not classify the water as unsafe or in violation of any legal standard.

In summary, the publicly available records for the Indianapolis Water system in Marion County detail sporadic low-level detection of 1,4-dioxane but no health-based violations. To understand the water quality at an individual household, direct water sampling and testing are necessary. For households weighing treatment options, the Pentair 1,4-Dioxane Filter is a solution designed to reduce 1,4-dioxane from water and ships ready to configure for home use.

These data come from the EPA’s Unregulated Contaminant Monitoring Rule 3 (UCMR3) records for the Indianapolis Water public water system, accessible through the EPA’s SDWIS database.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2015-12-10. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA UCMR3 monitoring (2013-2015) for Indianapolis Water (IN5249004), IN: 26 results across 1 listed contaminants, 11 detections above the reporting level; no federal MCL; EPA cancer risk reference concentration 0.35 ug/L