You fill a glass at the kitchen sink and catch a whiff of the gas pump. By the end of this guide you’ll know what to do in the first hour, who to call, how to test, and which treatment removes fuel chemicals.

First-hour checklist when well water smells like gasoline

Treat a fuel smell as a possible health hazard until a lab says otherwise. Based on guidance from the Wisconsin Department of Health Services (DHS) and the Illinois Department of Public Health (IDPH):

1. Stop drinking and cooking with the water. Wisconsin DHS says to stop if you can smell a gasoline odor or see an oily sheen. Use bottled water for drinking, cooking, formula and brushing teeth.
2. Ventilate. IDPH recommends opening doors and windows and running bathroom and kitchen exhaust fans.
3. Use cooler water. Hot water makes gasoline evaporate into the air faster. IDPH advises cooler showers and washing clothes in cold water.
4. If the smell is strong, stop bathing in it too. Wisconsin DHS says that at very high levels you should avoid washing, bathing or other uses as well. If the odor fills the room when the tap runs, skip the shower until your health department has reviewed a test result.
5. Call for help today (contacts below), noting when the smell started and any sheen.

Mistake to avoid: Don’t count on a pitcher or refrigerator filter. Fuel chemicals also escape into the air from showers, dishwashers and laundry, so a single-tap filter doesn’t protect the household.

If you smell fuel strongly in the air of your home, not just at the tap, get everyone out and call your fire department.

Why gasoline in well water is a health concern

The gasoline chemicals that matter most in water are the BTEX compounds (benzene, toluene, ethylbenzene and xylenes) and the additive MTBE, according to IDPH. IDPH notes that swallowing small amounts of gasoline can cause mouth, throat and stomach irritation, nausea, vomiting, dizziness and headaches. The EPA identifies benzene as a carcinogen.

The Virginia Department of Health points out that bathing and laundry also release vapors you breathe, especially in enclosed spaces like basements.

These are the EPA’s drinking water limits. Private wells aren’t regulated, but labs and health departments use these numbers, and some states are stricter.

Chemical	EPA limit	In ppb	EPA-listed health concern
Benzene	0.005 mg/L	5	Anemia, lower blood platelets, increased cancer risk
Toluene	1 mg/L	1,000	Nervous system, kidney or liver problems
Ethylbenzene	0.7 mg/L	700	Liver or kidney problems
Xylenes (total)	10 mg/L	10,000	Nervous system damage
MTBE	No federal limit	Advisory: 20 to 40	Taste and odor; health data limited

Where the gasoline is coming from

Fuel reaches a well when it leaks into soil and moves with groundwater.

Possible source	What to know	Who to contact
Leaking underground storage tank (UST)	The EPA calls leaking USTs a common source of groundwater contamination.	State UST program
Nearby gas station, current or former	Virginia’s health department suggests VOC testing for wells near a gas station or former station site.	State UST program, health department
Home heating oil tank	Leaking tanks and lines usually smell like fuel oil or diesel. Exempt from federal UST rules, but states may regulate them.	State environmental agency
Spills	Accidents, overfilled tanks, or refueling mowers and equipment near the well	State spill hotline

The EPA counts about 534,000 active petroleum USTs nationwide.

MTBE: the additive that travels farthest

According to the EPA, MTBE dissolves easily in water and doesn’t cling to soil, so it moves faster and farther in groundwater than other gasoline components and breaks down slowly. An old spill some distance away can still reach your well. The EPA says water with MTBE around 20 to 40 ppb or more tends to taste or smell like turpentine. The Minnesota Department of Health uses a health-based guidance value of 60 ppb, a reminder that agencies differ on chemicals without a federal limit.

Could it be something other than gasoline?

Sometimes. Wisconsin DNR lists iron bacteria and sulfur bacteria as other possible causes of a gasoline or fuel oil odor. Neither is a health threat.

But Wisconsin DNR is clear: rule out gasoline first. Stay on bottled water until a lab confirms no fuel chemicals. If the result is clean and you see red slime in the toilet tank, read about iron bacteria in wells.

Who to call about gasoline in well water

You don’t have to investigate a fuel leak yourself.

• Your state environmental agency. Most have a spill hotline and an underground storage tank program that investigates leaks. Maine, for example, runs a 24-hour spill hotline at 1-800-482-0777.
• Your state or county health department. They can explain health risks, interpret results and tell you when the water is safe to use.
• The EPA’s UST program. The EPA website lists each state’s UST contacts; states handle most of the day-to-day work.
• The EPA Safe Drinking Water Hotline at 800-426-4791, which the EPA suggests for private well owners with MTBE questions.

Mention nearby gas stations or tanks and whether neighbors notice the smell too.

How to test well water for gasoline

A routine bacteria and nitrate test will not detect fuel.

1. Ask a state-certified lab for a petroleum test. Wisconsin DNR recommends testing for gasoline range organics (GRO) or petroleum volatile organic compounds (VOCs). Ask that results include benzene, toluene, ethylbenzene, xylenes and MTBE.
2. Follow the lab’s sampling instructions exactly. VOCs escape into the air easily, so labs supply special containers and steps.
3. Sample from a tap before any filter or softener to see what’s in the raw well water.
4. Test again after installing treatment to confirm it works.

See our well water testing guide for help choosing a lab.

State cleanup funds and help paying for it

When a gas station or business caused the leak, the responsible party is generally expected to pay, with the state UST program overseeing cleanup. Some states also help homeowners directly:

• Wisconsin’s Well Compensation Grant Program covers wells contaminated by chemicals including gasoline and fuel oil. It pays 75% of eligible costs up to $16,000 (a $12,000 maximum grant) for families with income up to $65,000. Eligible costs include testing, treatment, a new well and temporary water. Work done before DNR approval isn’t reimbursed.
• Maine’s Ground and Surface Waters Clean-up and Response Fund can cover drinking water sampling and treatment equipment for oil contamination. Its homeowner guide lists a $500 standard deductible for oil storage under 1,320 gallons, and you must apply within 180 days of reporting.

Rules vary widely, so ask your state agency before paying for anything yourself.

Treatment that removes gasoline from well water

Because VOCs vaporize in showers, washers and dishwashers, the University of Nebraska-Lincoln Extension recommends point-of-entry (whole-house) treatment for them rather than a single-tap device.

Treatment	How it works	Limits
Point-of-entry granular activated carbon	Carbon beds grab organic chemicals as water passes through	The EPA notes MTBE doesn’t stick well to carbon, so more contact is needed. Media must be replaced.
Air stripping (aeration)	Air moves the chemicals out of the water and vents them outside	The EPA says MTBE needs high air-to-water ratios. Larger equipment.
New or deeper well, or public water	Avoids the contaminated groundwater	Wisconsin DNR says well work must be done by a licensed driller

The EPA reports these approaches have worked at individual homes. Choose equipment certified for the chemicals in your results and use a licensed installer. Our guide to whole-house water filters for wells explains how these systems fit together.

Pro tip: Carbon gets used up. Test the treated water on the schedule your installer or health department recommends, and keep records of every result and media change.

Frequently asked questions

Is it safe to shower if my well water smells like gasoline?

It depends on the level. IDPH advises cooler showers and good ventilation, and Wisconsin DHS says to avoid bathing at very high levels. If the smell is strong, don’t shower until your health department reviews a lab result.

Does boiling remove gasoline from well water?

Don’t rely on it. IDPH notes that hot water speeds the release of gasoline into the air, so boiling puts vapors into your kitchen. Use bottled water.

Can a heating oil tank contaminate my well?

Yes. Leaks from a home heating oil tank or its lines can reach groundwater. Federal UST rules exempt these tanks, so contact your state environmental agency.

How far can gasoline travel to reach a well?

There’s no set distance. The EPA says MTBE moves faster and farther in groundwater than other gasoline chemicals, so a distant leak can still reach a well.

Who pays to fix a well contaminated by a gas station?

Usually the tank owner, with state UST program oversight. States such as Wisconsin and Maine also offer homeowner funds.

Related guides

• Well water testing: what to test for and how often
• Is well water safe to drink?
• Whole-house water filter for well water

Sources

• Wisconsin DNR – My Water Smells Like Gasoline
• Wisconsin Department of Health Services – Chemicals: Gasoline
• Illinois Department of Public Health – Gasoline
• U.S. EPA – Learn About Underground Storage Tanks

This guide is for general information. If you smell gasoline in your water, stop drinking it and contact your state environmental agency or health department. If you smell fuel strongly in the air of your home, leave and call your fire department.