Cyclohexane in Drinking Water
Found in 14 water systems • vocs
Updated September 2026 • Data from EWG & EPA
What is Cyclohexane and Why Does It Matter?
CYCLOHEXANE IN YOUR TAP WATER: WHAT YOU NEED TO KNOW
What Is Cyclohexane and How Does It Get Into Our Water?
Cyclohexane is a colorless liquid chemical used primarily to manufacture nylon and other plastics. It's also used as a solvent in adhesives, paint thinners, and industrial cleaning products. When factories, refineries, or waste disposal sites don't contain these chemicals properly, cyclohexane seeps into groundwater and eventually reaches municipal water supplies. Improper disposal of industrial waste is the main culprit. The chemical can also leak from underground storage tanks at manufacturing facilities or contaminate soil at Superfund sites—areas designated by the EPA as severely polluted.
Once in the water system, cyclohexane doesn't break down quickly. It persists in groundwater for years, which is why even small industrial accidents can create long-term contamination problems. Unlike some contaminants that settle out or evaporate, cyclohexane stays dissolved in water, making it a persistent threat to communities near industrial areas.
Health Effects and Exposure Risks
The EPA hasn't established a strict drinking water standard for cyclohexane, which means there's no federal limit on how much can be in your tap water. However, this doesn't mean it's harmless. Animal studies show that cyclohexane exposure damages the liver and kidneys at high doses. In humans, limited research exists on long-term, low-dose exposure through drinking water—the kind of exposure most people face.
The health risk depends on concentration and duration of exposure. Occasional exposure to small amounts is unlikely to cause immediate harm. But regular consumption of water containing higher levels could potentially cause liver or kidney stress over time, especially in children whose bodies are still developing. Pregnant women may also want to be cautious, as some industrial solvents can affect fetal development, though specific data on cyclohexane is limited.
Current Regulatory Landscape
The EPA has not set a maximum contaminant level (MCL) for cyclohexane in drinking water, which is a significant gap. The Environmental Working Group (EWG) hasn't published a specific health guideline for cyclohexane either, making it harder for homeowners to know what level is truly safe. This regulatory silence doesn't reflect safety—it reflects the lack of comprehensive testing and research on this particular chemical.
What we do know is that 14 water systems across the United States have detected cyclohexane in their supplies. The highest level recorded was 51 ppb (parts per billion), while the average across detected systems was 6.5 ppb. None of these systems currently exceed EPA limits, simply because no limit exists. This is why staying informed matters: regulatory absence doesn't equal safety.
Geographic Patterns and Texas Concentration
All 14 water systems with detected cyclohexane are located in Texas. This concentration isn't random. Texas hosts major petrochemical refineries and plastics manufacturing facilities, particularly in the Houston area and along the Gulf Coast. These industrial operations create ongoing risk of cyclohexane contamination through spills, leaks, and improper waste handling.
The fact that all detections cluster in one state suggests this is an industrial geography problem, not a nationwide issue. However, communities in other states with similar industrial activity—Louisiana, Oklahoma, and parts of California—should be aware that cyclohexane contamination is possible.
Removing Cyclohexane From Your Drinking Water
Activated carbon filters effectively remove cyclohexane from drinking water. Both pitcher-style filters and under-sink carbon systems work well for this contaminant. Reverse osmosis systems provide even more comprehensive protection, removing cyclohexane along with dozens of other industrial chemicals and pollutants.
If you live in Texas, particularly near petrochemical facilities, testing your water is a smart first step. An Echo Water test reveals whether cyclohexane is present in your home's water. If it is, installing a carbon-based filter system provides reliable protection for your family's drinking water.
Regulatory Standards for Cyclohexane
| Standard | Level | Notes |
|---|---|---|
| Average Detected Level | 6.46 ppb | Across all tested systems |
| Highest Detected Level | 51 ppb | Worst-case system |
Cities With the Highest Cyclohexane Levels
| # | City | Detected Level | People Served |
|---|---|---|---|
| 1 | Dallas, TX | 51 ppb | 537 |
| 2 | Houston, TX | 12.80 ppb | 7,106 |
| 3 | Houston, TX | 7 ppb | 1,410 |
| 4 | Houston, TX | 3.50 ppb | 3,615 |
| 5 | Houston, TX | 3 ppb | 4,176 |
| 6 | Houston, TX | 3 ppb | 8,274 |
| 7 | Clayton, TX | 2.83 ppb | 402 |
| 8 | Clayton, TX | 1.60 ppb | 78 |
| 9 | Glendale, TX | 1.50 ppb | 357 |
| 10 | Dallas, TX | 1.20 ppb | 114 |
| 11 | Granbury, TX | 1.09 ppb | 405 |
| 12 | Pflugerville, TX | 0.85 ppb | 732 |
| 13 | Austin, TX | 0.60 ppb | 570 |
| 14 | Troup, TX | 0.50 ppb | 1,308 |
States Most Affected by Cyclohexane
How to Remove Cyclohexane From Your Water
Activated carbon effectively adsorbs cyclohexane due to its volatility and nonpolar nature, making it suitable for removal by standard activated carbon filters.
Standard pitcher filters and carbon block filters can provide some reduction of Cyclohexane, though effectiveness varies by brand and flow rate. For maximum protection, a certified RO system is recommended.
Activated carbon filters remove cyclohexane effectively, but cartridges must be replaced regularly as saturation reduces effectiveness.
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Shop Hydrogen FlaskFrequently Asked Questions
Is Cyclohexane in my drinking water?
Cyclohexane was detected in 14 water systems across the US. Check your city's water quality report to see if it affects your water supply.
What are the health effects of Cyclohexane in water?
Cyclohexane has been associated with various health concerns at elevated levels. The EWG has set health guidelines that are typically stricter than EPA legal limits.
Which city has the most Cyclohexane in its water?
Based on our analysis, Dallas, TX has the highest detected levels of Cyclohexane in its water supply.
How do I remove Cyclohexane from my water?
Reverse osmosis (RO) systems are generally the most effective at removing this contaminant. Check the filtration recommendations section for specific guidance.
Related Contaminant Guides
Data sources: Environmental Working Group (EWG) Tap Water Database, U.S. EPA Safe Drinking Water Information System (SDWIS)
Last updated: September 2026
Methodology: Contaminant levels are compared against both EPA legal limits (Maximum Contaminant Levels) and EWG health guidelines, which are often stricter and based on the latest scientific research.
