Office of
United States	Ground Water and
Environmental Protection Agency	Drinking Water
What is a carwash well?
What types of fluids are
injected into carwash wells?
Do injectate constituents
exceed drinking water
standards at the point of
What are the characteristics
of the injection zone of a
carwash well?
Are there any contamination
incidents associated with
carwash wells?
Are carwash wells vulnerable
to spills or illicit discharges?
How many carwash wells
exist in the United States?
Where are carwash wells
located within the United
How are carwash wells
regulated in states with the
largest number of this type of
Where can I obtain
additional information on
carwash wells?
Carwash wells are Class V underground injection control (UIC) wells used to dispose of
washwater at facilities that wash only the exterior of vehicles (sometimes called "wand
washes"). These are typically located at coin-operated, manual carwashes where people use
hand-held hoses to wash vehicles. Even though the term "carwash" is used, the category
includes wells that receive used washwater at facilities designed for washing all kinds of
vehicles, including cars, vans, trucks, buses, boats on trailers, etc.
Fluids that primarily contain detergents, road salts, sediments, and incidental contaminants that
may be washed from a vehicle's exterior.
Available sampling data indicate that the concentrations of antimony, arsenic, beryllium
cadmium lead, and thallium in the injectate typically exceed primary drinking water standards
and health advisory levels. Available data also show that ethylene glycol, methylene chloride,
naphthalene, and tetrachloroethene also have exceeded primary drinking water standards or
health advisory levels, indicating that degreasers may be working their way into the washwater
at some facilities. The pH, aluminum iron, and manganese levels in the injectate have exceeded
secondary drinking water standards.
Carwash wells are used in a variety of geological settings.
Two possible contamination incidents involving carwash wells have been reported in HI. The
nature and extent of contamination are unknown, but both wells were closed.
Although there are only two reported contamination incidents associated with carwash wells,
there is concern over the potential for such wells to be vulnerable to spills or illicit discharges.
Because an attendant is not usually on site, individuals may wash their engines or undercarriages
using degreasers, wash the exterior of their vehicles with chemicals other than common soap
solutions, or may pour used oil, antifreeze, or other hazardous materials down these drains.
There are up to 4,651 documented carwash wells and approximately 7,200 estimated carwash
wells in the United States. However, there is significant uncertainty regarding these estimates
because, in some cases, it is difficult to distinguish carwash wells from other kinds of
commercial or industrial wells.
Although carwash wells are documented in 14 states, 99 percent of the documented wells and 98
percent of the estimated wells are located in 9 states: AL, MS, NY, WA, MD, IA, WV, CA, and
Permit by rule: WV
Report discharge: CA
Individual permit'. AL, MS, NY, WA, MD, NH, and ME
Ban : IA
For general information, contact the Safe Drinking Water Hotline, toll-free 800-426-4791. The
Safe Drinking Water Hotline is open Monday through Friday, excluding federal holidays, from
9:00 a.m. to 5:30 p.m. Eastern Standard Time. For technical inquiries, contact Amber Moreen,
Underground Injection Control Program Office of Ground Water and Drinking Water (mail
code 4606), EPA, 401 M Street, SW, Washington, D.C., 20460. Phone: 202-260-4891. E-mail:
lno reen. alliber V/ epa. go\ . The complete Class VUIC Study (EPA/816-R-99-014, September
1999), which includes a volume addressing carwash wells without undercarriage washing or
engine cleaning (Volume 4), can be found at http://www.epa.gov/OGWDW/uic/cl5study.html.