Office of
United States	Ground Water and
Environmental Protection Agency	Drinking Water
What is a storm water	Storm water drainage wells are Class V underground injection control (UIC) wells used to remove
drainage well?	storm water or urban runoff from impervious surfaces such as roadways, roofs, and paved surfaces to
prevent flooding, infiltration into basements, etc. Hie primary types of storm water drainage wells are
bored wells, dug wells, and improved sinkholes. In addition, "lake level control wells" are used to
drain lakes to prevent overflow following heavy precipitation.
What types of fluids are	Primarily rain water and melted snow runoff,
injected into storm water
drainage wells?
Do injectate constituents
exceed drinking water
standards at the point of
What are the
characteristics of the
injection zone of a storm
water drainage well?
Are there any
contamination incidents
associated with storm
water drainage wells?
Available sampling data indicate that concentrations of antimony, arsenic, beryllium, cadmium,
chromium, cyanide, lead, mercury, nickel, nitrate, selenium, and certain organics in storm water
runoff have exceeded primary drinking water standards. Available sampling data also show that
concentrations of aluminum, chloride, copper, iron, manganese, total dissolved solids, zinc, and
methyl tert-butyl ether have exceeded secondary drinking water standards or health advisory levels.
Water quality data from FL indicate that lake level control well injectate has exceeded primary
drinking water standards or health advisory levels for turbidity, arsenic, pentachlorophenol, and fecal
colifonns, as well as secondary drinking water standards for iron, manganese, pH, and color.
In general, the point of injection for most storm water drainage wells is into sandy, porous soils, a
permeable coarse-grained unit, karst, or a fractured unit because these types of formations can readily
accept large volumes of fluids.
Contamination related to storm water drainage wells has been reported to various degrees in OH, KS,
WI, CA, WA, AZ, OK, TN, NY, IN, FL, KY, and MD. Several studies, however, do not clearly
distinguish contamination from storm water drainage wells versus more general, nonpoint source
pollution. Lake level control wells have been associated with two documented contamination
incidents in FL.
Are storm water drainage	Storm water drainage wells are generally vulnerable to spills or illicit discharges of hazardous
wells vulnerable to spills or	substances, as they are often located in close proximity to roadways, parking lots, and
illicit discharges?	commercial/industrial loading facilities where such substances are handled and potentially released.
How many storm water	There are approximately 71,000 documented storm water drainage wells and approximately 248,000
drainage wells exist in the	storm water drainage wells estimated to exist in the United States.
United States?
Where are storm water	About 81 percent of the documented wells are in seven western states: AZ (14,857), CA (3,743), WA
drainage wells located	(22,688), OR (4,148), ID (5,359), MT (4,000), and UT (2,890). Five other states contain
within the United States?	approximately 15 percent of the total wells: OH (3,036), FL (2,153), MI (1,301), MD (1,678), and HI
(2,622). There are approximately 200-250 lake level control wells in FL.
How are storm water	Permit by rule: IL, IN, MI, OH, WI (<10 ft. deep and constructed prior to 1994), MT, WY, ND, SD,
drainage wells regulated in	UT, CO, ID (< 18 ft. deep), OR, WA, KS, TN, RI
states with the largest
number of this type of	Individualpermit/registration system. AZ, CA, HI, ID (> 18 ft. deep), AL, FL, TX, NH, MD, NE, NY
Banned: NC, GA, WI (any new well since 1994 and wells >10 ft. deep since the 1930's), MN (for
"wells" that reach ground water)
Where can I obtain	For general information, contact the Safe Drinking Water Hotline, toll-free 800-426-4791. The Safe
additional information on	Drinking Water Hotline is open Monday through Friday, excluding federal holidays, from 9:00 a.m.
storm water drainage	to 5:30 p.m. Eastern Standard Time. For technical inquiries, contact Amber Moreen, Underground
wells?	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: moreen.amber(S?epa.gov.
The complete Class V UIC Study (EPA/816-R-99-014, September 1999), which includes a volume
addressing storm water drainage wells (Volume 3), can be found at