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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Hydroviv's Science Team

Our tech support team gets a lot of questions from people looking to purify their water by boiling or freezing it. Doing a quick web search, we learned that there is A LOT of bad information out there on the topic.

Will Boiling Or Freezing My Water Remove Lead, Arsenic, Mercury, PFAS, & Chromium 6?

No! Unfortunately, freezing or boiling water to purify it does not remove chemicals like lead, arsenic, mercury, chromium 6, PFAS, or barium. The only way to remove these chemicals is by using a quality water filtration system. If you'd like to find water filters that remove harmful contaminants from tap water, check out this Duke University/NC State water filter study. We have our favorite NSF/ANSI certified custom water filter, but there are other effective systems out there as well!

What Does Boiling My Water Protect Against?

In the United States, we are very fortunate that modern disinfection practices have nearly eliminated widespread waterborne illness. However, sometimes unplanned things do happen (e.g. water main breaks) which opens up an opportunity for biological contamination. When this happens, municipalities may issue a boil order or notice, because boiling water kills potentially dangerous microorganisms.

In the event your water company issues a boil water advisory, the CDC provides specific advice on what you should do. Their guidance covers many different types of water uses, and specifically advises you to boil the water you use for drinking and preparing food. They also advise that you use bottled or boiled water for brushing your teeth, and when giving water to pets. 

What Does Freezing My Water Protect Against?

Freezing things slows down the growth of bacteria, and is the reason why frozen foods can be stored for long periods of time.

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Why Optimization Matters

Have you every traveled to a different city and noticed that the water tastes different? That’s because the water chemistry is different, and more importantly, the problems present in the water are different too.

Around the country, millions of U.S. households have contaminants in their water that exceed public health goals, but the individual contaminates vary significantly state by state and even zip code by zip code. The issues in your water can be impacted by a variety of factors including the age of your home and city’s infrastructure, the natural geology of the region, and your home’s proximity to industrial sites, farms and military bases. Cities with older infrastructure like Pittsburg, Pennsylvania, and Jackson, Mississippi, for example, face issues with lead contamination, while new developments in the American Southwest may be lead-free, but record unsafe concentrations of arsenic.

To address the unique issues in your water, our Water Nerds analyze water quality reports from local, county, state, federal and academic sources, and then build a customized filter designed to match and screen out the specific contaminates and bad-tasting chemicals coming out of your tap. The result is a hyper-targeted and long-lasting filter designed to keep your water safe and tasting great.

Here are a few examples of how water differs around the country:

• Lead: Lead contaminates tap water differently than most pollutants, because lead comes from the plumbing, not the water supply. Many neighborhoods in older cities have lead-containing service pipes that connect water mains to residential plumbing. Homes with pipes installed before 1986 often also have lead-containing solder. Lead can enter the water supply when municipal corrosion controls fail (what happened in Flint, Michigan) or when water sits stagnant in pipes for long periods of time. Lead contamination is a problem in all major U.S. cities, but there have been significant issues reported recently in Newark, Pittsburgh, Nashville and New York City. Many common pitcher filters do not remove lead.Learn more>
• Arsenic: Arsenic is a naturally occurring toxic heavy metal that leaches into groundwater from surrounding rocks. Areas of the country where arsenic levels are high include Maine, Texas and much of the Southwest. Most common pitchers and fridge filters do not remove arsenic. Learn more>
• Chromium-6: Chromium-6, the cancer-causing chemical at the center of the Erin Brockovich story, is still used in a number of industrial processes including steel production, leather tanning, and textile manufacturing. It can enter local rivers and groundwater through waste, and despite notable media attention is still not well regulated. Homes located near current or former industrial facilities are most at risk. Learn more>

Chlorine vs. Chloramine:

Emma Schultz, M.S.  |  Scientific Contributor
Updated 12/1/2023 to include latest numbers of Superfund sites by state. 

Do you know where your nearest EPA Superfund Site is? Chances are there is one close by, given that one out of every five Americans lives within three miles of an EPA-designated major hazardous waste site. There are two sites located within four miles of my childhood home, in an idyllic and quiet suburb of St. Paul, Minnesota. I now live within the same distance of five sites -- and I had no clue. 

Superfund Sites - Environmental Hazards

What Is The Superfund Process?

The concept of EPA Superfund Sites is widely known and understood, but the intricacies of the program and the approach to hazardous waste mitigation are elaborate and prolonged, as can be expected of any federally-funded long-term project.

History: 

In December of 1980, President Jimmy Carter signed into law the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), now known better as Superfund, which authorized the EPA to remediate hazardous waste spills and sites, and obliged those responsible for the waste - the Potential Responsible Party - to either clean it up on their own dollar or offset the cost of EPA-led cleanup efforts. Superfund had abundant funding early in its existence due to taxes levied on chemicals and oil; those taxes, however, lapsed in 1995, and financing now comes from taxpayers.

Process and Stages:

There are multiple stages in the Superfund process once a site is identified, with the first step being a Preliminary Assessment or Site Inspection. If the site is an emergency such as a chemical spill, Removal Action is taken. Otherwise, Remedial Action is planned for, which often leads to years-long planning, cleanup, and remediation. Community involvement is frequently key during the early stages of Superfund designation, and the Technical Assistance Services for Communities (TASC) program is an outreach effort designed to connect with citizens and businesses for the duration of a Superfund's existence.

After initial study, EPA Superfund Sites are given a score on the Hazard Ranking System. If a site poses enough of a threat to environmental and human health, the EPA announces its addition to the National Priorities List (NPL), pending public comment and input. NPL sites are eligible for extensive, and often long-term, federal funding through the Superfund program. These NPL-listed sites are now officially Superfund sites.

Following NPL designation, a Remedial Investigation and Feasibility Study is conducted. The Remedial Investigation collects information on-site such as water and soil samples, and the follow-up Feasibility Study analyzes various cleanup methods. The EPA then selects the most suitable cleanup alternative and provides it to the community as a Proposed Plan.

A Record of Decision notes the cleanup alternative chosen for the site. In the Remedial Design phase, the cleanup plans are drawn up, and are finally acted upon in the Remedial Action stage. A goal of Remedial Action is to return sites to productive use as quickly as possible. Whether 'productive' means industrial, housing, commercial, or greenspace depends on conversations and input from the surrounding community.

A review of EPA Superfund Site cleanup efforts occurs every five years. If cleanup goals have all been met, a portion or whole of a Superfund site may then be listed for removal from the NPL. In theory, meeting all cleanup goals sounds achievable - especially given the lengthy planning and implementation phases - but there are many sites that remain listed decades later, because groundwater and soil are still polluted.

Where Can You Learn More About Superfund Sites?

Finding out if there are Superfund sites near your home is the first step that all concerned citizens should take. There are 10 Regional Superfund Community Involvement Offices around the country that exist to take your questions and concerns regarding existing or potential Superfund sites. 

Here is the latest list of states and the number of Superfund sites they contain. Be aware that not all toxic contaminants are on the list for contaminated sites to qualify for Superfund. For example, PFAS contaminated sites are not yet regulated under CERCLA. 

Resources for homeowners:

Eric Roy, Ph.D.  |  Scientific Founder

This past week, the Environmental Working Group (EWG) released a website where people punch in their zip code, and view contaminants found in their water. As a company that uses water quality data to optimize each customer’s water filter, we applaud EWG for putting in the enormous amount of time & effort to build the database so the public can learn about their water. Unfortunately, we are seeing that these data are being used to generate inflammatory headlines, which can leave consumers confused and unnecessarily panicked.

We will be updating this water quality database blog post as more questions come in. If you have your own question, please reach out to us (hello@hydroviv.com). One of our water nerds will do their best to get back to you very quickly, even if it’s outside of our business hours.

Frequently Asked Questions 

Updated July 31, 2017

Are All Potential Contaminants Listed In The EWG Tap Water Database?

No. The EWG Tap Water Database pulls data from municipal measurements, but municipalities are only required to test for certain things. Simply put, you can’t detect what you don’t look for. One example of this can be seen by punching in Zip Code 28402 (Wilmington, North Carolina) into the EWG Tap Water Database. GenX, a chemical that has been discharged into the Cape Fear River by Chemours since PFOA since 2010, is not listed, even though it’s been in the center of a huge topic of conversation for the past 2 months in the local media.

Why Is The “Health Guideline” Different Than The “Legal Limit?”

The two different thresholds use different criteria. For example, the “Health Guideline” cited by EWG for carcinogens is defined by the California Office of Environmental Health Hazard Assessment (OEHHA) as a one-in-a-million lifetime risk of cancer, while the “Legal Limit” refers to the MCL which is the limit that triggers a violation by EPA. The OEHHA's criteria are established by toxicological techniques, while the EPA limits are negotiated through political channels. We wrote an article that addresses this topic in much more detail for those who are interested.

Why Am I Just Learning About This Now?

The EPA's Safe Drinking Water Act requires municipalities to make water quality test data public in Consumer Confidence Reports. These reports are required to talk about the water's source, information about any regulated contaminants found in the water, health effects of any regulated contaminant found above the regulated limit, and a few other things. As discussed before, the data in the EWG report use different criteria than the EPA, and it's hard for people to make sense of what's what.

Are The Data Correct If My Water Comes From A Private Well?

No. The EWG Tap Water Database only has data for municipal tap water. Private wells are completely unregulated, and there's no requirement to conduct testing. If you'd like us to dig into our additional water quality databases to help you understand likely contaminants in your private well, we're happy to do so. We don't offer testing services, but we're happy to help you find an accredited lab in your area, give advice on which tests to run, and help you interpret the results! We offer this service for free.

What About My City's Water Quality?

Hydroviv makes it our business to help you better understand your water. As always, feel free to take advantage of our “help no matter what” approach to technical support! Our water nerds will work to answer your questions, even if you have no intention of purchasing one of our water filters. Reach out by dropping us an email (hello@hydroviv.com) or through our live chat. You can also find us on Twitter or Facebook!

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