Water Quality InformationWritten By Actual Experts


5 Things To Know About Arsenic In Drinking Water

Eric Roy @ Saturday, April 8, 2017 at 1:27 pm -0400

Eric Roy, Ph.D.  | Scientific Founder

There has been some recent press coverage about arsenic contamination in drinking water. Predictably, our email and support line have been filled with questions on the topic. While we have written other articles in the past about well water in general, the purpose of this article is to specifically answer FAQs about health effects of arsenic in drinking water, and to dispel some myths about arsenic in drinking water.

Why Should I Care About Arsenic In Drinking Water?

Arsenic is a toxic substance that is linked to a long list of health problems in humansFor 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. Simply put, the health effects of arsenic in drinking water are bad news, and you can't see, taste or smell it in water.

What Are The Different Types Of Arsenic Found In Drinking Water?

Nearly all arsenic found in drinking water is inorganic. There are two types of inorganic arsenic, Arsenic(III) and Arsenic(V), and both are toxic. The ratio of the two forms depends on what part of the country you live in, and whether or not your water is chlorinated, becasue chlorine quickly converts Arsenic(III) to Arsenic(V). 

How Does Arsenic Contaminate Drinking Water?

While arsenic-containing pesticides can contaminate water, most arsenic contamination comes from the area's natural geology. This means that arsenic can contaminate seemingly pristine water in certain parts of the country, including private wells. The map below is from USGS and shows arsenic groundwater concentrations. In this map, you can see prevalent arsenic hot spots in places like Maine, Wisconsin, Texas, and various areas across the western part of the US.

Map Of Arsenic Concentrations In Groundwater

How Much Arsenic Is Toxic?

EPA acknowldeges that there is no safe level of arsenic for drinking water (MCLG = 0), but has set a regulatory limit of 10 parts per billion (ppb) for arsenic in drinking water. When this level was negotiated, scientists were pushing for a 3 ppb, but ultimately EPA decided that the cost of lowering the allowable level to 3 ppb would "not justify the benefits." We recently wrote a dedicated article on how EPA determines acceptable levels of contaminants in drinking water that you can read if you would like more information on this topic.

It's also worth pointing out that a large number of people in the US draw water from private wells, and that most well water "checks" do NOT test for arsenic. If you live in an area on the map with hot spots, we highly recommend getting arsenic testing done by a qualified water testing lab. Test kits from hardware stores are not accurate, and cheap TDS meters and "water testers" tell you nothing about arsenic. 

What Can I Do To Reduce Exposure To Arsenic?

A growing number of people are realizing that regulatory limits are not always in line with current studies, and are choosing to eliminate arsenic, lead, and chromium 6 from their drinking water, even if their city is "in compliance" with EPA regulations.

Unlike lead, which leaches into water from pipes, arsenic comes from the source water itself, so flushing pipes or replacing plumbing will not reduce arsenic concentrations. Boiling water also does NOT remove arsenic. Arsenic must be removed from water using a filter that is specifically designed to do so.

Whole House Filters

Some whole house filters can be configured to remove arsenic. We do not typically recommend these systems becasue they are very expensive, and there's no need to filter the water that is used for most household applications (e.g. flush toilet).

Point Of Use Filters

The most cost-effective way to remove arsenic, chromium 6, and other contaminants is through a point of use filter. When shopping for these systems, we encourage you to make sure that the filter actually filters arsenic (most don't). While we believe that our advanced under sink water filtration systems have unique benefits and use filtration media that effectively remove both Arsenic(III) and Arsenic(V), some systems that use reverse osmosis can be a good choice for people who are willing to accept the downsides. No matter what... make sure that your filter removes what you think it does!

If you have any questions about filtering arsenic from your home's water, we encourage you to take advantage of Hydroviv’s “Help No Matter What” approach to technical support, where we will help you select an effective water filter system, even if it’s not one that we sell. This free service can be reached by emailing support@hydroviv.com

Other Articles We Think You'll Enjoy:

Why Whole House Filters Are Usually A Waste Of Money
The Most Important Things To Know About Well Water
Why TDS Meters Are Largely A Marketing Gimmick

5 Things That Most People Don't Realize About Well Water

Analies Dyjak @ Wednesday, November 2, 2016 at 3:28 am -0400

Roughly 15 percent of Americans get their tap water from private wells, and this percentage can rise to 40% in rural states like Maine and Vermont. It's no surprise that we receive a lot of questions from people with wells who are are concerned about water quality.

1. Getting A Well “Checked” Is Not The Same As Comprehensive Water Testing

There is a misconception that if someone gets their private well “checked,” it will reveal water quality problems. Unfortunately, that’s not the way it works. A basic water screening has a lot of "blind spots" and gives no information about levels of lead, arsenic, chromium 6, mercury, or VOCs unless you test specifically for those chemicals. Some states have certain testing requirements, but the scope of testing varies from state to state, and most states do not require comprehensive testing. Many banks require that certain water tests be conducted before they will issue a mortgage, but the goal of this testing is often to ensure that there are no faulty systems in the home, not to protect the health of the residents.

Bottom line: The well's owner is responsible for having tests run. Don't assume that the tests that were done as part of the home buying process were comprehensive.

2. Well Water Contamination Often Comes From Natural Sources, Not Humans

Some private well owners are surprised to learn that they have contaminated water, because there are no obvious contamination sources nearby. This is because some contaminants (like arsenic) can occur naturally groundwater at unsafe levels. 

3. Well Water Is Often Corrosive & Can Leach Lead From Plumbing

The lead crisis in Flint put a spotlight on the fact that corrosive water can leach lead from pipes, soldered joints, and plumbing fixtures. Unfortunately, a lot of well owners don't realize that well water can be inherently corrosive, so if a their plumbing predates 2014 (when lead-free standards were fully adopted for home plumbing components), there is potential for lead to leach into the tap water.

4. Contaminant Concentrations (And Recognized Safe Levels) Change With Time

We cannot emphasize enough that people should get their wells tested on a regular basis, because contaminant concentrations and thresholds for “safe” water both change over time.

For example, we commonly hear homeowners in the Northeast and Southwest tell us that they tested their water for arsenic "a few years ago" and everything was fine. They are often surprised to learn that EPA recently lowered the concentration of arsenic that is considered to be “safe." The maximum contaminant level (MCL) used to be 50 parts per billion but was changed to 10 parts per billion a few years ago. This means that many wells with arsenic concentrations that were considered “safe” by EPA a few years ago are now considered unsafe.

5. Private Well Owners Are Responsible For Monitoring Their Water Quality, Not EPA

Private wells are not regulated by EPA or State Regulators, so the owners (or prospective owners) are responsible for all well water quality testing. However, figuring out which tests to do and making sense of the results can be confusing. Some states have guidelines and recommendations, but even these can be confusing and contradictory.

Often times, prospective home owners turn to a real estate agent for advice on water quality testing, but we often hear from people who received terrible advice. Most of the time, the mistakes are honest, but there are times when it looks like the agent was trying to facilitate a quick sale.

Ultimately, ensuring water quality of a private well is the individual responsibility of the well’s owner or prospective owner. In support this responsibility, we encourage people to take advantage our Technical Support Team’s “Help At All Costs” policy, and lean on us to provide guidance on which lab to select in your area, which tests to run, and to help interpret the results. This free (no obligation service) can be reached by emailing us (support@hydroviv.com) or by using the live chat function on this page.

We do not have financial agreements or arrangements with water quality test labs, and we do not “over-prescribe” testing.

Other Great Articles That We Think You'll Enjoy:

5 Things You Need To Know About Chromium 6 In Drinking Water
Why TDS Meters Don't Tell You Anything About Lead Contamination
Does Boiling Or Freezing My Water Purify It?

Why Does EPA Allow “Acceptable Amounts” of Toxic Chemicals In Drinking Water?

Analies Dyjak @ Friday, November 4, 2016 at 10:55 pm -0400

Anya Alvarez |  Contributor   

After a hard-hitting ad campaign ran by one of our competitors, many were surprised to learn that EPA allows “acceptable amounts” of certain toxic chemicals. If you’re like others concerned who don’t want to deal “acceptable levels” of toxicity in water, this article will explain the regulatory definitions and provide tips on how to regulate the water in your home.

Understanding Water Quality Definitions

If something is toxic, you probably don't want it in your water. So why does the government allow small levels of toxic chemicals in our water? Currently the EPA has in place unenforceable water quality goals and enforceable drinking water standards. Below I highlight the difference between the two, why the EPA allows toxic levels, and how to reduce exposure to toxic chemicals in drinking water.

Non-Enforceable Water Quality Goals

Maximum Contaminant Level Goal (MCLG) - The MCLG refers to the concentration of a contaminant that does not pose any health risk to humans. However, one must not forget that MCLGs are unenforceable and therefore have no regulatory limits. For example, the MCLG for Arsenic is 0 parts per billion, but the EPA limit is 10 parts per billion. This is EPA's way of saying "we don't want anyone to drink arsenic, but it would be too expensive to fully remove it."

Enforceable Water Quality Standards/Limits

Maximum Contaminant Level (MCL) - The MCL is the maximum level of a contaminant allowed in water.  Unlike the MCLG, the MCL is an enforceable limit.

Action Level (AL) - For other contaminants like lead, EPA uses a different term (Action Level) for the regulatory water quality standard. Using this definition, a municipality is in violation only if 10% or more of the samples exceed the AL. To put it a bit differently:  up to 10% of the samples can exceed the Action Level, and the water is still in full compliance.

Are Regulatory Water Quality Limits For Contaminants In Line With The No-Risk Goals?

You can still be at risk, even if water quality limits meet the “no-risk goals” of the EPA. The table below shows a few chemicals where allowed concentration is higher than the no-risk goal.  The complete list can be seen here.


No-Risk Goal

EPA Enforceable Limit


0 ppb 10 ppb
Benzene 0 ppb 5 ppb
Lead 0 ppb 15 ppb
PCBs 0 ppb 0.5 ppb
TCE 0 ppb 5 ppb

Why Does EPA Allow Any Amount Of Toxic Chemicals In Drinking Water?

EPA knows it is not economically feasible for municipalities to yield contaminant free water for large populations, the MCLs are categorized between the health risk involved to the population and the financial cost to remove chemicals such as lead from water.


EPA acknowledges that no safe level of lead exists in drinking water (MCLG=0 ppb). However, the EPA acceptable drinking water standards allows 10% of the samples to be over 15 ppb. Homes with plumbing connections and fixtures and cities with a large number of lead-containing water service lines, make it economically unfeasible, politically unacceptable, and extremely difficult to enforce mandates. Doing so would force municipalities to dig up lead pipes and require all citizens to replace their plumbing. To avoid this, the EPA makes publicly available reports, mentioning the involved risks if citizens drink the water, while also entailing steps residents can to minimize exposure. However, municipalities often try to hide lead levels because they are ultimately reliable. Click here for an example from Newark, New Jersey.


Arsenic, which occurs naturally in some groundwater sources, does not come from municipal infrastructure or residential plumbing. Because of this, arsenic isn’t economically/politically reasonable to remove it. As a result, municipalities disclose the levels of arsenic in the water report:

"If arsenic is less than the MCL of 10 ppb, your drinking water meets EPA’s standards... EPA’s standard balances the current understanding of arsenic’s possible health effects against the costs of removing arsenic from drinking water." Check out an example of this on page 3 of this Clarkdale, Arizona report. 

How To Further Reduce Exposure To Toxic Chemicals In Drinking Water

Since there are no guarantees that contaminants won’t exceed the enforceable limits, there are steps you can take to protect yourself. This can include installing a quality water filter and remaining up-to-date on water quality reports for your local area. As always, we encourage everyone to take advantage of Hydroviv's "Help No Matter What" technical support policy, where we answer questions related to drinking water and water filtration, even if you have no desire to purchase our products.

Other Articles We Think You Will Enjoy:
5 Things You Need To Know About Chromium 6 In Drinking Water
Why TDS Meters Don't Tell You Anything About Lead Contamination
Does Boiling Or Freezing My Water Purify It?