1,4 Dioxane

Update: March 2018

Marana Water, in its efforts to continuously provide high quality service and product to its customers, recently began a voluntary water quality sampling program to gain more information about our water system.  Based on information recently received from other water providers in the region, Marana Water was informed that an unregulated compound called 1,4-dioxane had the likelihood of being present within the groundwater under the Marana Water service area.  Recent testing by the department has shown that some of our drinking water wells have this compound present.

What is 1,4-dioxane? How is it used?

1,4-dioxane is solvent stabilizer that is commonly used with other chemicals and products such as paints and waxes. It is also found in many regular household items such as shampoos, colognes, perfumes, and even some food products.

What is an unregulated compound?

An unregulated compound means that the compound is not part of the mandatory water quality testing that the department is required to do per state and federal rules. The United States Environmental Protection Agency (USEPA) is currently examining 1,4-dioxane as a potential drinking water contaminant, but has not created a maximum contaminant level regulation at this time. This compound has been found across the nation and has the ability to remain in the environment for a long time.  While 1,4-dioxane is being studied by the USEPA, they have issued a health-based advisory for drinking water systems to use as a benchmark. The current health-based guidance value is 0.35 parts per billion, or micrograms per liter.  To give an idea on what a part per billion means, it is like one drop of water in a 22,000 gallon swimming pool or one inch within 16 miles. Some of the Marana Water wells tested show concentrations that are above this health based guidance value.


The information below will help identify the testing results for specific neighborhoods. The chart on the left, reflects sampling data from October 2016 through December 2017. The colors correspond with the water systems in the map on the right. If you click on the image, it will enlarge for better viewing of the results.


Is the quality of my water OK?

All Marana Water systems meet the current required federal and state water quality standards for drinking water. However, as your local water professionals, we also know that not every chemical compound or microbiological risk is regulated. By staying aware of our local environment and the environment of our nation, we can conduct additional, voluntary water quality sampling to help us understand and identify potential issues before they become a drinking water regulated item. Activities like this sampling program will allow us to effectively plan for possible additional infrastructure and treatment options in a proactive, not reactive, manner.

how can 1,4-dioxane in the water affect my health?

Toxicological studies have yet to positively prove 1,4-dioxane is carcinogenic. However, the EPA is currently studying the effects of 1,4-dioxane in drinking water. They currently believe it is "likely" to cause cancer with long term exposure, though not definitive. The current guideline for drinking water is on a calculated risk potential that a person may have a health affect after drinking 2 liters per day for 70 years of water that is at or above the health advisory of 0.35 ppb. Since it is so widely used in common household products, people are exposed to 1,4-dioxane in many areas of their lives.

What can i do to reduce my exposure to 1,4-dioxane?

Review the list of compounds included in personal care and household products to identify if they contain any of the following words: PEG, Polyethylene, Polyethylene Glycol, Polyoxyethylene, -oxynol, -eth. Exposure to 1,4-dioxane can often be associated with the use of personal care products that contain these types of ingredients.

What are the next steps?

Marana Water has scheduled additional sampling of our wells and delivery systems over the next several months.  Having information on what is present in our environment with more data will allow us to determine why this compound is present in our region and what steps we may want to explore to mitigate any occurrence of this in the future. We plan to work with the other water and wastewater utilities in the area to combine as much of our research data to develop a complete picture. As the department gathers additional information, we will provide updates to the community through the Marana Water website, www.MaranaWater.com.