Water Quality InformationWritten By Actual Experts

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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Michelle Scire  |  Scientific Contributor

What Is 1,2,3 Trichloropropane And Where Does It Come From?

1,2,3 Trichloropropane (TCP) is a synthetic chemical that is commonly used as an industrial solvent, cleaning and degreasing agent, and paint and varnish remover.  In California’s Central Valley, widespread TCP contamination was caused by a now-banned fumigant DBCP, which was used to kill nematodes (small worms that live in the soil). When applied to the soil, TCP leaches from the deeper soil to groundwater. When DBCP was banned in 1977 by the EPA, it was commonly used on over 40 crops in California. Unfortunately, TCP is persistent in the environment, and as of November 2017, 395 of the 5863 wells used by public water supplies had levels of TCP that exceeded the California regulatory limit. When looking at a map of contaminated wells (above), you will see a strip right up the center of California from south of Bakersfield to Sacramento with some prominent outliers in Los Angeles, San Diego, Salinas, San Jose, San Francisco, and Chico counties. 

Why Do We Care About TCP?

TCP is some nasty stuff. In the short-term, high levels of inhalation exposure to TCP can cause irritation of eyes, respiratory tract and skin, and has the ability to depress the central nervous system. Moreover, studies in rodents have confirmed it may affect memory, focus and muscle coordination. Long term exposure studies have found exposure in rodents can lead to liver and kidney damage as well as reduced body weight and tumor growth. To get an idea of how toxic TCP is, the 5 part per trillion MCL (legal limit) is equivalent to a single drop of water being diluted into about 5.5 olympic sized swimming pools!.

Timeline of Public Knowledge Related To TCP Toxicity

Data from: HERE

What Took Regulation Of TCP So Long?

While it’d be great if regulatory bodies were able to act quickly, the reality is that regulations take time, often decades to execute. In the case of TCP specifically, Cindy Forbes, the deputy director for Californiawater board’s drinking water program, insists that TCP regulation was a “top priority,” but explained that they had limited resources preventing them from reaching“the finish line.” In California, the process to establish a maximum contaminant level (ie regulatory limit) includes: conducting their own peer-reviewed research, evaluating cost of detection and cleanup, as well as allowing public comment (which undoubtedly includes comments from companies responsible for contamination). Forbes claims, “It’s my priority, it’s the board’s priority,” but one has to wonder what the word priority means when there is scientific research going back 25 years explicitly showing the repercussions of this contaminant. There is only one carcinogen with a lower state public health goal for drinking water, and that is dioxin.

What Can Be Done To Treat Water That Has Been Contaminated With TCP?

Large Scale TCP Remediation Techniques

Because of the contamination primarily leaching into the ground water in California's Central Valley, ground water remediation methods have been established. TCP can be removed with traditional methods such as, “pump and treat granular activated carbon filters (GAC), in-situ oxidation, permeable reactive barriers (zero-valent zinc), dechlorination by hydrogen-releasing compounds, and emerging biodegradation techniques.” A new method was developed recently using, “in-line, pressurized advanced oxidation process (HiPOx) that has the ability to remove TCP from groundwater to below 0.005 μg/L.” The treatment techniquewill depend on the level of contamination in groundwater or soil being treated. While these methods are indeed effective, they are expensive and require long planning/execution periods.

Small Scale (Residential) TCP Removal of TCP

If your home’s water is contaminated with TCP, and large-scale treatment isn’t happening in an acceptable time frame, some residential water filters do remove TCP. Our advice is to find a water filter that is advertised to remove volatile organic compounds (VOCs), and ask the manufacturer for a data sheet that shows effective removal of TCP specifically. 

If you have any more questions about 1,2,3 Trichloropropane contamination, we encourage you to reach out to our “Help No Matter What” technical support through live chat or email (hello@hydroviv.com). Our Water Nerds are happy to answer any questions you may have!

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