Arsenic is a naturally occurring element found in rocks, soil, and groundwater throughout many parts of the United States. While arsenic can also result from certain industrial activities, naturally occurring arsenic is the primary source found in many private wells and some public water supplies.
Because arsenic has no noticeable taste, smell, or color in water, many homeowners are unaware that it may be present. This guide explains where arsenic comes from, why it matters, how it is regulated, and practical steps you can take to reduce exposure.
Looking for a countertop gravity-fed filtration system? The Big Berkey® Water Filter is our most popular stainless steel system for everyday household use.
What Is Arsenic?
Arsenic is a naturally occurring element found throughout the Earth's crust. Small amounts are present in rocks, soil, groundwater, and surface water around the world.
Although arsenic occurs naturally, elevated levels can also result from historical mining, industrial processes, agricultural activities, and naturally occurring geological formations.
In drinking water, arsenic is most commonly found in groundwater drawn from wells.
Where Does Arsenic in Drinking Water Come From?
Most arsenic found in drinking water originates naturally as groundwater passes through rocks and minerals containing arsenic. As water slowly moves underground, small amounts of arsenic may dissolve into the water supply.
Additional sources may include:
- Natural geological formations
- Groundwater aquifers
- Historical mining operations
- Industrial activities
- Agricultural runoff in some areas
The amount of arsenic present varies considerably depending on local geology and water sources.
Where Is Arsenic Most Common?
Arsenic can occur almost anywhere, but naturally elevated levels are more common in certain regions of the United States.
Areas with higher naturally occurring arsenic may include parts of:
- California
- Nevada
- Arizona
- New Mexico
- Colorado
- Utah
- Texas
- The Midwest
- New England
Many public water systems routinely monitor for arsenic, while private well owners are generally responsible for testing their own water.
Can You Taste or Smell Arsenic?
No.
Arsenic has no noticeable taste, odor, or color in drinking water. Water can appear completely clear while containing measurable arsenic.
The only reliable way to determine arsenic levels is through laboratory testing.
Potential Health Concerns
According to the U.S. Environmental Protection Agency (EPA), long-term exposure to elevated arsenic levels in drinking water may increase health risks.
Scientific studies have associated long-term exposure with possible effects involving:
- Skin changes
- Cardiovascular health
- Diabetes
- Nervous system effects
- Certain types of cancer
Health effects depend on numerous factors, including concentration, duration of exposure, and individual health conditions.
EPA Drinking Water Standard for Arsenic
The EPA has established a Maximum Contaminant Level (MCL) of 10 parts per billion (10 µg/L) for arsenic in public drinking water systems.
Public water utilities are required to routinely monitor arsenic levels and take corrective action if concentrations exceed this federal standard.
Private well owners are responsible for testing and maintaining the quality of their own drinking water.
Should Private Well Owners Test for Arsenic?
Yes.
If your home relies on a private well, periodic testing is recommended because arsenic cannot be detected without laboratory analysis.
Testing is especially important if:
- Your home uses groundwater from a private well.
- You live in an area known for naturally occurring arsenic.
- You have never tested your well water.
- Nearby wells have reported elevated arsenic levels.
How Can Homeowners Reduce Arsenic Exposure?
If you're concerned about arsenic in your drinking water, consider these practical steps:
- Review your local Consumer Confidence Report (CCR) if you receive municipal water.
- Have your water tested by a certified laboratory if necessary.
- Test private well water periodically.
- Use a high-quality point-of-use filtration system designed to reduce arsenic levels.
- Replace filter elements according to manufacturer recommendations.
Berkey® Water Filters and Arsenic Reduction
Berkey® countertop gravity-fed water filter systems are designed for everyday household use.
When equipped with Black Berkey® Replacement Filters, Berkey® systems are designed to reduce a broad range of unwanted contaminants, including arsenic, while leaving beneficial minerals in the water.
For most households, the Big Berkey® Water Filter provides an excellent balance of capacity, convenience, and daily performance.
Choosing the Right Berkey® System
| System | Capacity | Recommended For | Product |
|---|---|---|---|
| Travel Berkey® | 1.5 Gallons | Singles & Couples | View Product |
| Big Berkey® | 2.25 Gallons | Most Families | View Product |
| Royal Berkey® | 3.25 Gallons | Larger Families | View Product |
| Imperial Berkey® | 4.5 Gallons | High Daily Water Use | View Product |
| Crown Berkey® | 6 Gallons | Large Homes & Offices | View Product |
Related Drinking Water Guides
Learn more about common drinking water contaminants and filtration:
- Drinking Water Contaminants Reference Guide
- Lead in Drinking Water Guide
- PFAS in Drinking Water Guide
- VOCs in Drinking Water Guide
- Hard Water Guide
Frequently Asked Questions
What causes arsenic in drinking water?
Most arsenic found in drinking water occurs naturally as groundwater moves through rocks and minerals that contain arsenic. Industrial and historical mining activities may also contribute in some locations.
Can boiling water remove arsenic?
No. Boiling water does not remove arsenic and may slightly increase its concentration as water evaporates.
Can I see arsenic in my water?
No. Arsenic has no noticeable taste, odor, or color. Laboratory testing is required to determine whether it is present.
Should private wells be tested?
Yes. Since private wells are not regulated like public water systems, regular testing is recommended, especially in regions where naturally occurring arsenic is more common.
Which Berkey® system is best for most households?
The Big Berkey® Water Filter is the most popular choice for families because it offers an ideal combination of capacity and countertop convenience.
Where can I buy replacement filters?
You can shop genuine replacement elements on our Berkey® Replacement Filters page.
Final Thoughts
Arsenic is one of the most important naturally occurring drinking water contaminants because it cannot be detected by sight, taste, or smell. Fortunately, homeowners can take practical steps to better understand their water quality through testing and by using an appropriate point-of-use filtration system.
If you're looking for a versatile countertop gravity-fed filtration system for everyday use, explore the Big Berkey® Water Filter. Its combination of capacity, ease of use, and high-performance filtration makes it our most popular choice for families.