Please Stop Using TDS Testers To Evaluate Water Quality
Eric Roy, Ph.D. | Scientific Founder
We get quite a few questions about TDS meters (like this one) and TDS measurements. While we love when people take steps to learn more about their water, some people (including journalists from reputable publications- Example #1 Example #2) have used TDS meters to draw false conclusions about water quality, which incited fear in people already in the midst of a terrible water quality crisis. In this article, we answer the questions that we get asked the most about TDS measurements and TDS meters.
What is TDS? What Does A TDS Meter Measure?
TDS stands for Total Dissolved Solids which is related to the total charged mineral content of water. TDS can be easily determined by measuring the conductivity of a water sample, which is exactly what inexpensive TDS probes do. If you start with deionized water (which has a TDS of zero), and expose it to minerals that contain sodium, calcium, and magnesium ... the water's TDS rises. This is why there's no such thing as deionized water in nature. Depending on a region’s geology, natural TDS levels can vary across the US, and this variability has nothing to do with the water quality (except in extreme cases when the water is too salty to drink).
What Does a TDS Meter Not Measure?
Because TDS is an aggregate measure of charged compounds in water, uncharged things like motor oil, gasoline, many pharmaceuticals, and pesticides do not contribute to a TDS measurement. For example, the glass on the left in this article's header image contains deionized water with Malathion (an organophosphate pesticide) dissolved into it at 100 times higher concentration than allowed by the EPA for drinking water, and the TDS probe reads 000.
What About Lead, Arsenic or Chromium 6?
Even though these toxic metals are charged when dissolved in water, a TDS meter does not give meaningful information about their presence or concentration in water. There are two main reasons for this:
- A TDS meter is a nonselective measurement and cannot differentiate among different ions. A more sophisticated piece of equipment is needed to perform those types of measurements. The value of 184 that was measured using a TDS meter in a prominent Huffington Post Article was not the lead concentration… it was the water's natural TDS level (which is dominated by minerals like calcium, magnesium, and sodium).
- A TDS tester is not sensitive enough to measure toxic levels of lead, chromium-6, or arsenic, even if they are present in a sample. This is because the reading displayed on an inexpensive TDS meter is in parts per million, while things like lead, chromium-6, and arsenic are toxic at part per billion concentrations (1000 times lower). Using a TDS meter to measure ppb lead concentrations in tap water is like trying to use a car’s odometer to measure a child's height…. It's the wrong tool. For example, the water sample shown on the right hand side of this article's header image has lead levels that are 100x the EPA limit, and the TDS reading teetered between 000 and 001.
To reiterate: Meaningful lead and arsenic measurements cannot be made using a TDS meter (or any other handheld device). They must be measured by trained staff in analytical laboratories that use much more sophisticated scientific equipment.
Do Hydroviv Filters Lower TDS?
No. Hydroviv’s filters selectively filter harmful things from your water (like lead, chromium-6, pesticides, pharmaceuticals, petroleum products, disinfection byproducts), and things that make water taste and smell bad (chlorine, chloramine, sulfur). Hydroviv’s home water filtration systems don’t remove minerals like calcium and magnesium because there’s no reason to. In fact, we use some types of filtration media that actually add minerals to the water, so TDS levels in water filtered through a Hydroviv system are sometimes slightly higher than unfiltered water.
Should I Buy a TDS Meter To Test My Water For High TDS Levels?
No. There is absolutely no reason to drink low TDS or deionized water. If you are concerned about water quality, put the money toward the purchase of an effective drinking water filter that removes harmful contaminants from your water.
What If I Already Have a TDS Meter?
If you have a TDS meter (like this one), we recommend giving it to a curious child who has an interest in science! Use the opportunity to teach them about dissolved minerals by encouraging them to test different types of water (e.g. distilled, rain, river, lake) and try to explain their findings! Feel free to reach out to us at (firstname.lastname@example.org for educational ideas involving TDS meters).
If you mail it to us, we’ll make sure it finds a good home in a school classroom, and we’ll send you a $20 coupon code to use on Hydroviv's website.
Other Great Articles That We Think You'll Enjoy:How EPA Regulations For Lead Are Protecting Municipalities, Not Citizens
What Science Says About Fluoride In Tap Water
EPA Proposes New Definition of "Waters of the United States"
Analies Dyjak & Matthew Krug
February 14th 2019: The Department of the Army and the Environmental Protection Agency posted the newly proposed “Waters of the United States” rule to the Federal Register. At its core, the proposed EPA WOTUS rule limits the water that EPA can regulate and monitor. By narrowing the scope of WOTUS definitions, this basically gives industries a roadmap of where it’s okay to pollute without the need for permitting. This is a big deal for the 45 million Americans who rely on well water for drinking and bathing. So, why should you care about the definition of waters of the United States?
"Waters of the United States"
This definition, also known as “WOTUS” has been up for debate for decades, and it’s interpretation has seen several Supreme Court cases. This proposed rule determines what waters the federal government is able to regulate and monitor. Generally, “waters” have traditionally been navigable waters such as oceans, rivers, ponds, and streams. As our scientific understanding of hydrology has improved, the scope of what are considered “waters” has expanded.
What Is Not Protected Under The Proposed Rule?
WOTUS definitions name certain waters as “excluded,” which, in this case, means they do not have a surface water connection. This means that groundwater, ephemeral streams, ditches, prior converted cropland and some wetlands and ponds are not included. This is a continued rollback of environmental regulations - and the 2019 EPA WOTUS rule proposal may have the farthest-reaching implications of all.
How Does This Proposed Rule Affect Drinking Water?
This rule puts the 45 million Americans that use private wells as a primary source of drinking water at risk. Private wells are not regulated by federal, state, or local governments, and agencies are not required to test for contaminants or ensure “compliance.” A 2006 study by the USGS concluded that private wells are already contaminated with various types of agricultural runoff, solvents, fumigants and inorganic compounds, the most common being arsenic and nitrates. Arsenic is a naturally occurring organic compound, that enters groundwater as bedrock weathers overtime. However, nitrates are used in fertilizers and enter both surface and groundwater from agricultural runoff. 8.4% of the wells tested in this study were in exceeded the federal standard for nitrates (we have an article dedicated specifically to nitrates in groundwater). Further, EPA does not provide recommended criteria or standards for private well users. By rolling back protections, private well users are being further kept in the dark.
How Did They Arrive At this Rule?
The proposed EPA WOTUS rule is primarily based off a majority opinion by Justice Scalia in the Supreme Court case Rapanos v. United States. Scalia’s interpretation favored “traditional waters,” and steered away from Justice Kennedy’s “significant nexus theory.” In his majority opinion, Scalia wrote that federal protections should cover:
“...only those wetland with a continuous surface connection to bodies that are waters of the United States.”
The American Farm Bureau dominated the conversation at the press conference for the proposed EPA WOTUS rule in early December of 2018. Industries lobbied hard to limit the scope of jurisdictional waters. In a political landscape where there is an abundance of legislation grandfathered in to protect the chemical, fossil fuel, and agricultural industries, it should come as no surprise that the current administration did not break from tradition. The agricultural industry is not the only institution who will benefit from this proposed rule. Chemical manufacturing companies have to go through a rigorous permitting process determined by state or federal governments (NPDES) which regulate pollution. But now, with a clearly defined and reduced scope of what constitutes a water of the United States, these companies are able to map out how to circumvent regulation.
The federal government has designated this as “economically significant”
This means that the proposed rule with have an annual effect on the economy of $100 million or more.
This proposed WOTUS definitions puts the 15% of the country at further risk of groundwater contamination. This population of people are now on their own in terms of monitoring their drinking water and keeping up with land use changes. Our science team will be submitting public comments on this proposed rule, which will be available on our website in the upcoming weeks. We encourage our readers to do the same thing! CLICK HERE for the link to the WOTUS public comment page.Other Articles We Think You Might Enjoy:
5 Reasons Why Bottled Water Isn't The Solution To Drinking Water Contamination
Nitrates In Drinking Water
Why Runoff From Farms Is A Big Deal
5 Reasons Why Bottled Water Isn't The Solution To Drinking Water Contamination
Analies Dyjak | Policy Nerd
Whenever severe water contamination impacts a community, people (and media outlets) tend to jump to bottled water as the only water contamination solution.
The bottled water industry has managed to convince vulnerable consumers that their product is inherently safer than what’s coming out of their taps. Oftentimes, this isn’t the case. So why is bottled water bad? The reality is that bottled water is associated with a host of ethical, environmental and regulatory problems. Drinking bottled water is not a long-term solution to water contamination, and we should critically examine its role as water quality crises continue to pop up across the country. Here are our main problems with the bottled water industry to give you a better idea of why bottled water is bad.
1) Bottled Water Companies Use The Same Source As Tap Water
According to the FDA, bottled water companies are permitted to package and sell water from municipal taps, artesian wells, mineral water, natural springs, and drilled wells. Surprisingly enough, they aren’t required to disclose the source water itself. If you’re looking for transparency, municipal systems are required to publish an annual Consumer Confidence Report (CCR) that discloses characteristics about the source water, treatment techniques, and other distribution information. The bottled water industry also frequently packages and distributes groundwater from dug wells. Groundwater can often be more susceptible to pollution than surface water because it’s not regulated by the federal government. Groundwater acts as a catchment for surface water runoff and agricultural pollution, not to mention its increased risk of arsenic contamination.
2) Bottled Water and Tap Water Have Almost Identical Standards
People are often surprised to learn that there’s virtually no difference between the regulations for bottled water and tap water. The Environmental Protection Agency regulates tap water and the Food and Drug Administration regulates bottled water. The allowable concentrations of contaminants are identical for both, with the exception of lead. The standard for lead in bottled water is 5 parts per billion, as opposed to 15 parts per billion in tap water. This is because during bottling production, water should never come in contact with older lead service pipes the same way municipal water does. Arsenic can be present in groundwater as a result of natural weathering of bedrock. Exposure to arsenic in drinking water can result in cancers in various organs, including skin, bladder, lung, kidney, liver, and prostate. Non-cancerous health effects include neurological damage, such as peripheral neuropathy.
3) Impacts On The Environment
It’s well-documented that single-use plastic water bottles wreak havoc on the environment. Plastics are made from petroleum, which is a fossil fuel and a non-renewable resource. Companies often tout their commitment to reducing plastic consumption by weight, but this has no bearing on the volume at which it’s produced. You may be familiar with “Trash Island,” in the Northern Pacific Ocean. This phenomenon is the result of decades of poor waste management and excessive production of various types of plastic. According to a 2016 study by the Ellen Macarthur Foundation, the ocean will contain more plastic by weight than fish by the year 2050. Polyethylene Terephthalate (PET) is the main ingredient in plastic water bottles. PET takes over 400 years to decompose in the environment and its constituents can often take longer to degrade. Chemicals like Bisphenol A (BPA) have since been phased out of plastic production, but are still very much present in the environment and will continue to be released as older plastics degrade.
4) False Advertising
Marketing schemes deceive consumers into believing that companies use pristine source water. The packaging uses carefully curated images of mountain-top creeks and streams to suggest pure, untainted products. The reality is bottled water hardly ever comes from the sources depicted on the label.
5) Ethical Dilemma
Nestle, a company with a long track record of unscrupulous business practices, owns deep aquifers throughout California, a state which has been experiencing drought-like conditions for several decades. The expensive equipment purchased by Nestle allows the company to extract water in a way that tribes and municipalities cannot afford to do. Similar companies have been known to use their purchasing power to acquire land, pushing tribes and municipalities out of the conversation. Problems arise when drought-stricken or contaminated communities are unable to afford the same resources as bottled water companies.
While bottled water offers some measure of immediate relief to a severe drinking water crisis, it is in no way a long-term water contamination solution. Companies often sell the same water that’s feeding municipal systems. Not to mention, EPA and FDA have almost identical regulations for both tap and bottled water. There’s also an inherent cost associated with bottled water, which varies depending on the brand. Finally, a huge part of why bottled water is bad is that scientific data confirms the importance of reducing plastic pollution on a global scale. Municipal providers offer greater transparency and are required to disclose information about the source water.Other Articles We Think You Might Enjoy:
Microplastics In Water: What You Need To Know
Endocrine Disruptors In Drinking Water
Water Conservation and Water Quality In The Sports Industry
Problems We Found In Omaha, Nebraska's Drinking Water
Ernesto Esquivel | Water Nerd
For Hydroviv’s assessment of Omaha, Nebraska's drinking water, we collected water quality test data from the city’s Consumer Confidence Report and the U.S. Environmental Protection Agency. We cross referenced Omaha's water quality data with toxicity studies in scientific and medical literature. The water filters that we sell at Hydroviv are optimized to filter out contaminants that are found in Omaha's drinking water.
Where Does Omaha Source Its Drinking Water?
Omaha draws its tap and drinking water from the Missouri River, Platte River, and the Dakota Sandstone aquifer.
Lead in Omaha’s Drinking Water
Based on the 2017 water quality report, lead levels in Omaha ranged from less than 0.5 to 14.9 parts per billion. 10% of taps had levels over 6.4 parts per billion, which is in compliance with the loose EPA standard of 15 parts per billion. However, if you were to ask toxicologists, pediatricians, or the CDC they would all tell you that there is no safe minimum level of lead. Lead is a neurotoxin that can have serious developmental effects on children.
Arsenic in Omaha’s Drinking Water
Arsenic is a heavy metal that typically leaches into groundwater as surrounding bedrock naturally weathers overtime. According to the most recent data, Arsenic concentrations ranged from 2 to 5.07 parts per billion in Omaha's tap and drinking water. EPA set a Maximum Contaminant Level of 10 parts per billion for Arsenic, but several health and regulatory agencies believe this level should be reduced to 1 or even 0 parts per billion. Arsenic is a toxic substance that is linked to a long list of health problems in humans. For example, arsenic can cause a number of different cancers (e.g. skin, bladder, lung, liver, prostate), as well as create non-cancerous problems with cardiovascular (heart/blood vessels), pulmonary (lungs), immune, neurological (brain), and endocrine (e.g. diabetes) systems. Hydroviv recommends purchasing a filter that is optimized to remove Arsenic from your drinking water, especially if you’re serviced by a private well.
Disinfection By-Products in Omaha’s Drinking Water
When water treatment facilities sanitize the water with chemicals such as chlorine, different contaminants can be created. These types of contaminants are called Disinfectant by products or DBPs. They are split into two categories: Total Trihalomethanes (TTHMs) and Haloacetic Acids-5 (HAA5). Concentrations of TTHMs averaged 43 parts per billion but were detected as high as 86.3 parts per billion. HAA5 concentrations averaged 19.3 parts per billion but were detected as high as 40.4 parts per billion. For a bit of perspective, EPA set a Maximum Contamination Level of 80 parts per billion for TTHMs and 60 parts per billion for HAA5.
Chromium 6 In Omaha’s Drinking Water
Chromium 6 is an unregulated toxic metal that's associated with metal processing, tannery facilities, chromate production, stainless steel welding, and pigment production. Concentrations of Chromium 6 were found to be ranging from 0.13 parts per billion to 1.4 parts per billion. These levels are nearly 70 times higher than the concentration determined to have a negligible impact on cancer risk. EPA has acknowledged that Chromium 6 is a known human carcinogen through inhalation, but is still determining its cancer potential through ingestion of drinking water. Lung, nasal and sinus cancers are associated with Chromium 6 exposure. Ingestion of extremely high doses of chromium 6 compounds can cause acute respiratory disease, cardiovascular, gastrointestinal, hematological, hepatic, renal, and neurological distress which may result in death.
Synthetic Organic Contaminants in Omaha's Drinking Water
Di(2-ethylhexyl)phthalate was also detected in Omaha's drinking water. This chemical is known for its ability to make plastic flexible. A toxicology report has shown that this chemical is known to cause reproductive problems in young males, stomach pains, and is labeled as a probable carcinogen. EPA set a Maximum Contaminant Level of 6 parts per billion for this contaminant. The Omaha water quality problem report detected concentrations of these chemicals ranging from less than 2 parts per billion to 3.11 parts per billion.
Other Articles We Think You Might Enjoy:
Lead Contamination In Drinking Water
Disinfection Byproducts In Drinking Water: What You Need To Know
5 Things To Know About Arsenic In Drinking Water
Problems We Found In Oklahoma City's Drinking Water
Ernesto Esquivel | Water Nerd
For Hydroviv’s assessment of Oklahoma City’s drinking water problems, we collected water quality test data from Oklahoma City and the U.S. Environmental Protection Agency. We cross referenced their water quality data with toxicity studies in scientific and medical literature. The water filters that we sell at Hydroviv are optimized to filter out contaminants that are found in Oklahoma City’s drinking water.
Where Does Oklahoma City Source Its Drinking Water?
Oklahoma City sources its drinking water from seven surface water reservoirs from five Oklahoma counties. They include Canton Lake, McGee Creek, Lake Atoka and Sardis Lake, Lake Overholser, Lake Hefner and Lake Stanley Draper. These reservoirs feed into three OKC drinking water treatment plants.
Arsenic In Oklahoma City Drinking Water
Arsenic is a heavy metal that typically leaches into groundwater as surrounding bedrock naturally weathers overtime. According to this years report, concentrations of Arsenic in Oklahoma City’s water were detected at just under 2 parts per billion. It should be noted that although these number were reported in the 2017 report, the samples were collected in 2013. The federal Maximum Contaminant Level for Arsenic in drinking water is 10 parts per billion, but regulatory agencies acknowledge that this level should be reduced to 1 or even 0 parts per billion. Arsenic is a toxic substance that is linked to a long list of health problems in humans. For example, arsenic can cause a number of different cancers (e.g. skin, bladder, lung, liver, prostate), as well as create non-cancerous problems with cardiovascular (heart/blood vessels), pulmonary (lungs), immune, neurological (brain), and endocrine (e.g. diabetes) systems. Hydroviv recommends purchasing a filter that is optimized to remove Arsenic from your drinking water, especially if you’re serviced by a private well.
Disinfection Byproducts In Oklahoma City Drinking WaterOklahoma City’s municipal water is contaminated with disinfection byproducts or DBPs. DBPs are formed when chlorine-based disinfectants are routinely added to the water supply to kill bacteria, and react with organic matter. They are split into two categories: Total Trihalomethanes (TTHMs) and Haloacetic Acids-5 (HAA5). Concentrations of HAA5 averaged 43.65 parts per billion and reached levels as high as 50.8 parts per billion. Concentrations of TTHMs averaged 70.87 parts per billion, but had levels as high as 76.73 parts per billion. For a bit of perspective, EPA's Maximum Contaminant Level for HAA5 is 60 parts per billion and 80 parts per billion for TTHMs. Disinfection Byproducts are a category of emerging contaminants which means they have been detected in drinking water, but the risk to human health is unknown. Regulatory agencies have very little knowledge about the adverse health effects of DBPs, and their toxicity. EPA has stated that they have been linked to an increased risk of bladder cancer, as well as kidney, liver, and central nervous system problems.
Chloramine In Oklahoma City Drinking Water
While most municipalities use chlorine as the primary drinking water disinfectant, Oklahoma City’s drinking water is disinfected with chloramine. Chloramine is primarily responsible for what many customers report as the “bad taste” or “pool smell” of tap water. Concentrations were detected at 3.62 parts per million in the Hefner water treatment plant, 3.32 parts per million in the Draper water treatment plant , and 3.28 parts per million in the overholser water treatment plant. These levels are just under the EPA Maximum Contaminant Level of 4 parts per million. Unlike chlorine, chloramine does not dissipate if a container of water is left in the refrigerator overnight. Most one-size-fits-all water filters use filtration media that doesn’t do a great job removing chloramine, but the filters that we design and build at Hydroviv for OKC's drinking water use a special filtration media that is purposefully designed to remove chloramine.
It’s important to note that only a handful of contaminants are required to be included in annual Consumer Confidence Reports, and that there are hundreds of potentially harmful unregulated contaminants that aren’t accounted for. If you’re interested in learning more about water filters that have been optimized for Oklahoma City’s tap water quality problems, feel free to visit www.hydroviv.com to talk to a Water Nerd on our live chat feature or send us an email at email@example.com.Other Articles We Think You Might Enjoy:
What's The Difference Between Chlorine and Chloramine?
Problems We Found In Tucson's Drinking Water
Analies Dyjak | Policy Nerd
For Hydroviv’s assessment of Tucson, Arizona’s drinking water quality problems, we collected water test data from the city’s Consumer Confidence Report and the U.S. Environmental Protection Agency. We cross referenced Tucson's water quality data with toxicity studies in scientific and medical literature. The water filters that we sell at Hydroviv are optimized to filter out contaminants that are found in Tucson’s drinking water.
Where Does Tucson Source Its Drinking Water?
Tucson sources its drinking water from 200 groundwater wells and the Colorado River.
Chromium 6 In Tucson's Drinking Water
Chromium 6 is a highly toxic metal that is currently unregulated by the EPA. In recent years, Tucson has had a major problem with this dangerous contaminant. Chromium 6 pollution is associated with metal processing, tannery facilities, chromate production, stainless steel welding, and pigment production. The city of Tucson detected levels of Chromium 6 as high as 94 parts per billion and averaged 4.72 parts per billion. These levels are nearly 4700 times higher than the concentration determined to have a negligible impact on cancer risk. EPA has acknowledged that Chromium 6 is a known human carcinogen through inhalation, but is still determining its cancer potential through ingestion of drinking water. Lung, nasal and sinus cancers are associated with Chromium 6 exposure. Ingestion of extremely high doses of chromium 6 compounds can cause acute respiratory disease, cardiovascular, gastrointestinal, hematological, hepatic, renal, and neurological distress which may result in death.
Perfluorinated Compounds In Tucson’s Drinking Water
This years water quality report for Tucson, Arizona included test data from two Perfluorinated Compounds: Perfluorooctane-sulfonic acid (PFOS) and Perfluoro-1-hexanesulfonic Acid (PFHxS). Concentrations of PFOS were detected as high as 56 parts per trillion, and averaged 28 parts per trillion. Concentrations of PFHxS were detected as high as 420 parts per trillion and averaged 210 parts per trillion. The Agency for Toxic Substances and Disease Registry (ATSDR) recently recommended setting a Minimum Risk Level of 20 parts per trillion for PFOS, but is still researching the toxicity profile of PFHxS. These data from the ATSDR are preliminary and the effects to human health are still unknown. This category of chemicals are “emerging contaminants” which means they are thought to pose a potential threat to human health and the environment, but haven't yet been regulated. Perfluorinated Substances contribute to environmental contamination largely due to the fact that they are highly resistant to the degradation processes, and thus persist for many years in water, air and can enter the food chain via bioaccumulation in certain animal species.
Arsenic In Tucson’s Drinking Water
Arsenic is a heavy metal that typically leaches into groundwater as surrounding bedrock naturally weathers overtime. The concentrations of Arsenic in Tucson’s water were detected as high as 7 parts per billion. The federal Maximum Contaminant Level for Arsenic in drinking water is 10 parts per billion, but regulatory agencies acknowledge that this level should be reduced to 1 or even 0 parts per billion. Arsenic is a toxic substance that is linked to a long list of health problems in humans. For example, arsenic can cause a number of different cancers (e.g. skin, bladder, lung, liver, prostate), as well as create non-cancerous problems with cardiovascular (heart/blood vessels), pulmonary (lungs), immune, neurological (brain), and endocrine (e.g. diabetes) systems. Hydroviv recommends purchasing a filter that is optimized to remove Arsenic from your drinking water, especially if you’re serviced by a private well.
It’s important to note that only a handful of contaminants are required to be included in annual Consumer Confidence Reports, and that there are hundreds of potentially harmful unregulated contaminants that aren’t accounted for. If you’re interested in learning more about water filters that have been optimized for Tucson's tap water quality, feel free to visit www.hydroviv.com to talk to a Water Nerd on our live chat feature or send us an email at firstname.lastname@example.org.Other Articles We Think You Might Enjoy:
5 Things To Know About Chromium 6 In Drinking Water
Perfluorinated Compounds In Drinking Water
Arsenic In Drinking Water