Analies Dyjak  |  Hydroviv Policy Analyst

Updated 3/13/2024

What Is Groundwater?

Groundwater is submerged water located among soils, cracks and pores, beneath the surface of the earth. Groundwater travels down a gradient through geological formations and is stored in aquifers. Aquifers act as holding tanks for readily available drinking water. Rain patterns, hydrology, and ice/snow melt are the primary factors that affect how quickly a groundwater supply is replenished, also known as recharge. The recharge rate is how quickly aquifers are able to replenish the groundwater level after an influx of water.

Why Is Groundwater So Important?

It’s simple: It supplies drinking water to millions of Americans whose municipalities draw from groundwater sources (e.g. Miami, Tucson, Lincoln), as well as the 15% of people living in the U.S that use private wells as their drinking water source. In fact, the US Geological Survey estimates that 140 million people, or about 40% of the nation's population get their drinking water from groundwater sources, which include both municipal (city) water and private wells. Groundwater is also a major supplier of surface water in oceans, lakes, streams, ponds and wetlands. Crucial habitats and ecosystems are dependent on an influx of healthy groundwater, as well as surface water for public drinking water usage.

How Can Groundwater Become Polluted?

There are two major ways that groundwater can accumulate toxic chemicals:

1. Natural-occurring chemicals: In some regions of the country, things like arsenic, radium, and uranium are naturally found in the rocks that come in contact with groundwater. 
2. Man-made Pollution: Groundwater can also become contaminated by human activities including: agriculture, industry, landfills, localized pollution, and anything that involves discharging effluent into a surrounding waterway. Polluted water seeps through soil until it reaches the water table, where it can travel freely depending on the hydrology and permeability of an aquifer. Contaminants that are particularly soluble in water (such as PFAS and 1,4-dioxane) can migrate into groundwater aquifers that serve as drinking water sources. Polluted groundwater then slowly travels through aquifers until reaching nearby surface water or being pumped through a well and consumed as drinking water.

Are There Federal Regulations That Protect Groundwater?

The Ground Water Rule was created in 2006 by the U.S Environmental Protection Agency to improve and inspect drinking water sources that may be potentially polluted by fecal contamination. This rule does not address human-made toxic and carcinogenic groundwater contamination. Additionally, the Ground Water Rule is specific to public water systems and excludes private wells.

The Federal Government does not oversee or have anything to do with regulating private wells. In fact, private wells aren’t even regulated by the Safe Drinking Water Act. This means that it’s at the discretion of the homeowner to determine if their private well water is safe for consumption. Testing private well water is extremely expensive and at times ineffective if the contamination type and concentration is continuously changing. Additionally, The Federal Government doesn’t regulate many of the contaminants in questions today.

How Can I Learn More About My Water?

If you have any questions about groundwater and regional water information, we encourage you to take advantage of Hydroviv’s “Help No Matter What” approach to technical support, where we will help you, even if you have no desire to purchase one of our water filters. Truth be told, we have access to a much larger pool of water quality data than is easily accessible to the general public. You can reach our water nerds by emailing hello@hydroviv.com or opening a Live Chat window in the bottom corner of this screen.

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Analies Dyjak, M.A. | Head of Policy and Perspectives

**Updated 9/21/2021 to include recent studies

What Is 1,4-Dioxane?

1,4-dioxane is a synthetic industrial chemical, typically used as a stabilizer for chlorinated solvents. It was historically used in the production of 1,1,1-trichloroethane (TCA), which was phased out in 1985 after scientists determined it to be an ozone-depleting substance. Today, 1,4-dioxane is not typically added directly to consumer products but can be an unintentional byproduct in certain plastics. It’s introduced as a trace contaminant in certain ingredients, most commonly detergents, foaming agents, emulsifiers and solvents, including Polyethylene Glycol or PEG.  

Is 1,4-Dioxane Regulated?

1,4-dioxane in drinking water is not federally regulated under the Safe Drinking Water Act, even though EPA has classified it as “likely to be carcinogenic to humans by all exposure routes.” There are health advisories in place but a Maximum Contaminant Level (MCL) does not exist. This means that unless a state has its own enforceable standard, utility providers are not required to remove it from drinking water. 1,4-dioxane is regulated by the Occupational Safety and Health Administration (OSHA) for indoor workplace air quality. 1,4-dioxane is on the fourth drinking water Contaminant Candidate List and is also part of the Third Unregulated Contaminant Monitoring Rule. In 2019, New York State became the first state to regulate 1,4-Dioxane by establishing Maximum Contaminant Limits (MCL) of 10 ppb in cosmetics, and 2 ppb in personal care and household cleaning products by 12/31/2022, which will be further reduced to 1 ppb by 12/31/2023.  

How Does 1,4-Dioxane Enter Drinking Water?

1,4-dioxane has contaminated drinking water through both groundwater and surface water. Many instances of groundwater contamination are a result of 1,4-dioxane being used in various manufacturing processes. According to the Agency for Toxic Substances and Disease Registry, 1,4-dioxane can easily travel into groundwater because it is extremely soluble in water and does not stick to soil particles. 

1,4-dioxane contamination on Long Island, New York was a result of routine spills or direct disposal of solvents to the ground from manufacturing operations between the 1950s to the 1990s. 

1,4-dioxane was used in the manufacture of medical filters in Ann Arbor, Michigan. The methods of waste disposal used between 1966 to 1986 resulted in 1,4-dioxane being released into the environment, causing widespread groundwater contamination. 1,4-dioxane in drinking water continues to be a concern for local residents, even decades after the pollution was first discovered and remediation was to have been taking place. 

1,4-Dioxane has also been released into surface water, both into rivers or public sewage systems. Sources of contamination include effluent from industrial facilities as well as wastewater treatment plants.   

1,4-Dioxane Health Effects In Drinking Water

1,4-dioxane can harm the eyes, skin, lungs, liver, and kidneys. As previously stated, 1,4-Dioxane is classified by the US EPA as a likely human carcinogen. Like other contaminants, the dose and duration of exposure affect the likelihood and severity of adverse 1,4-dioxane health effects.

Why is 1,4-Dioxane So Hard To Remove From Drinking Water?

1,4-Dioxane is completely soluble in water. It dissolves completely, even at high concentrations. It also does not readily evaporate. Traditional treatment methods are ineffective at removing 1,4-Dioxane from drinking water, so a few larger municipalities have begun to incorporate specialized methods for 1,4-Dioxane removal in their processes. These can be prohibitively expensive for smaller municipal water suppliers, so there is not likely to be a widespread solution for 1,4-Dioxane removal implemented any time soon.  

What Can I Do if I Have 1,4-Dioxane in My Water?

There are no federal testing standards for 1,4-Dioxane, so we are unable to provide removal data. Hydroviv’s filters have however been tested and certified by NSF to remove VOC’s with similar chemical properties to 1,4-Dioxane. Most submicron pore size carbon block filters are able to address 1,4-dioxane, with the exception of granular activated carbon. A slower flow rate will also assist the carbon block filter by ensuring enough contact time with the 1,4-Dioxane and the filtration media. For example, Hydroviv drinking water filters incorporate carbon into our submicron block and at our 1 gallon/minute flow rate.