Propene in Drinking Water
Found in 27 water systems • vocs
Updated September 2026 • Data from EWG & EPA
What is Propene and Why Does It Matter?
PROPENE: WHAT YOU NEED TO KNOW ABOUT THIS CHEMICAL IN YOUR WATER
What Is Propene and Where Does It Come From?
Propene (also called propylene) is a colorless gas used to manufacture plastics, chemicals, and other industrial products. It enters water supplies primarily through industrial discharge and leaks at manufacturing facilities. Refineries, petrochemical plants, and plastic production facilities are the main culprits. When these operations aren't properly maintained or regulated, propene can seep into groundwater or be released directly into surface water sources that feed municipal water systems. Unlike some contaminants that occur naturally in soil or rock, propene is entirely human-made—a sign of industrial activity in your region.
Health Effects and Exposure Concerns
The good news: propene at the levels found in drinking water is unlikely to cause immediate harm. The average concentration detected is 0.911 ppb (parts per billion), which is quite low. However, the maximum recorded level reached 6.7 ppb in one system, showing that exposure can vary significantly depending on where you live.
The EPA has not established a maximum contaminant level (MCL) for propene, meaning there's no federal drinking water standard. This doesn't mean it's harmless—it means there simply isn't enough evidence yet to set a mandatory limit nationwide. Animal studies suggest propene may cause developmental issues at very high exposures, but human drinking water studies are limited. The Environmental Working Group (EWG) has not published a specific health guideline for propene either, reflecting the uncertainty around its effects at low environmental concentrations.
The Regulatory Gap
This is where things get murky. Because propene lacks an EPA MCL, water utilities aren't required to monitor for it or remove it. The contaminant was detected in 27 water systems, all in Texas, but because there's no regulatory requirement, these systems aren't obligated to treat it or even report it to customers. This regulatory gap means propene can persist in drinking water without triggering any alarm bells or enforcement action.
The lack of a standard doesn't reflect safety—it reflects limited research. Propene is on the EPA's candidate contaminant list, meaning it's being evaluated for future regulation. If you're in Texas and concerned about industrial chemical contamination, this is worth monitoring as standards evolve.
Why Texas Is Affected
All 27 detected cases of propene in drinking water occurred in Texas, which makes sense geographically. Texas hosts one of the largest concentrations of petrochemical and refining facilities in the United States, particularly along the Gulf Coast and in the Houston area. These industrial hubs require massive amounts of propene for manufacturing, and aging infrastructure, accidental spills, and routine discharges can contaminate nearby groundwater and surface water sources.
The state's rapid industrial growth has sometimes outpaced water infrastructure upgrades, creating conditions where contaminants from manufacturing can reach drinking water supplies. If you live near a refinery, petrochemical plant, or industrial corridor in Texas, your water system is more likely to encounter propene.
How to Remove Propene From Your Water
Since propene isn't regulated, most municipal systems don't treat for it. You'll need to take action yourself. Activated carbon filters are effective at removing propene—they work by trapping organic chemicals as water passes through. A whole-house carbon filtration system provides protection for all your water uses, while under-sink or pitcher filters protect your drinking and cooking water specifically.
Reverse osmosis systems offer another option, removing up to 99% of organic contaminants including propene. These are more expensive but highly effective for anyone in an industrial area concerned about multiple chemical contaminants.
Start by testing your water if you live in Texas near industrial facilities. Once you know what you're dealing with, you can choose the right filtration approach for your home and family.
Regulatory Standards for Propene
| Standard | Level | Notes |
|---|---|---|
| Average Detected Level | 0.91 ppb | Across all tested systems |
| Highest Detected Level | 6.70 ppb | Worst-case system |
Cities With the Highest Propene Levels
| # | City | Detected Level | People Served |
|---|---|---|---|
| 1 | Austin, TX | 6.70 ppb | 423 |
| 2 | Fort Worth, TX | 0.70 ppb | 682 |
| 3 | Aledo, TX | 0.70 ppb | 5,010 |
| 4 | Lake Worth, TX | 0.70 ppb | 4,700 |
| 5 | Edgecliff Village, TX | 0.70 ppb | 3,788 |
| 6 | Haslet, TX | 0.70 ppb | 3,579 |
| 7 | Trophy Club, TX | 0.70 ppb | 9,526 |
| 8 | Burleson, TX | 0.70 ppb | 49,089 |
| 9 | Crowley, TX | 0.70 ppb | 17,330 |
| 10 | Forest Hill, TX | 0.70 ppb | 13,020 |
| 11 | Fort Worth, TX | 0.70 ppb | 955,900 |
| 12 | Haltom City, TX | 0.70 ppb | 46,260 |
| 13 | Hurst, TX | 0.70 ppb | 38,510 |
| 14 | Keller, TX | 0.70 ppb | 45,400 |
| 15 | Westworth Village, TX | 0.70 ppb | 2,597 |
States Most Affected by Propene
How to Remove Propene From Your Water
Propene is a volatile organic compound that activated carbon filters effectively remove through adsorption, and it can also be removed by aeration due to its high volatility.
Standard pitcher filters and carbon block filters can provide some reduction of Propene, though effectiveness varies by brand and flow rate. For maximum protection, a certified RO system is recommended.
Activated carbon filters are effective at removing propene, making basic pitcher filters with carbon cartridges a viable option for this specific contaminant.
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Shop Hydrogen FlaskFrequently Asked Questions
Is Propene in my drinking water?
Propene was detected in 27 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 Propene in water?
Propene 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 Propene in its water?
Based on our analysis, Austin, TX has the highest detected levels of Propene in its water supply.
How do I remove Propene 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.
