&EPA
Office of
United States	Ground Water and
Environmental Protection Agency	Drinking Water
CLASS V UIC STUDY FACT SHEET
AQUACULTURE WASTE DISPOSAL WELLS
What is an aquaculture waste
disposal well?
What types of fluids are
injected into aquaculture waste
disposal wells?
Do injectate constituents
exceed drinking water
standards at the point of
injection?
What are the characteristics of
the injection zone of an
aquaculture waste disposal
well?
Are there any contamination
incidents associated with
aquaculture waste disposal
wells?
Are aquaculture waste disposal
wells vulnerable to spills or
illicit discharges?
How many aquaculture waste
disposal wells exist in the
United States?
Where are aquaculture waste
disposal wells located within
the United States?
How are aquaculture waste
disposal wells regulated in
states with the largest number
of this type of well?
Where can I obtain additional
information on aquaculture
waste disposal wells?
Aquaculture waste disposal wells are Class V underground injection control (UIC) wells used to
dispose of water used for the cultivation of marine and freshwater animals and plants under
controlled conditions.
Aquaculture effluent that includes fecal and other excretory wastes and uneaten aquaculture food.
The primary chemical and physical constituents of these wastewaters are therefore nitrogen- and
phosphorus-based nutrients and suspended and dissolved solids. The effluent may also contain
bacteria and chemicals, pesticides, and/or aquaculture additives.
Available analytical data for aquaculture effluent and injectate suggest that the concentrations of
most parameters are generally below applicable drinking water standards. Contaminants that may
exceed the drinking water standards under some circumstances include turbidity and possibly
nitrite and nitrate. The secondary drinking water standard for chloride is also exceeded in the
wastewater from some seawater-based operations, but as long as these wastes are injected to saline
aquifers, they pose no threat to underground sources of drinking water.
The injection zone for aquaculture wastewater is characterized by relatively high porosity, as y
aquaculture wastewaters typically have significant suspended solids content. Seawater-based y
aquaculture operations in Hawaii inject wastewater into brackish or saline aquifers that flow y
seaward. Little information is available regarding other aquifers receiving aquaculture injectate.
No contamination incidents related to aquaculture wastewater disposal have been reported.
Information about the threat of contamination posed by these wells is also inconclusive. For
example, in ID, an aquaculture well is known to inject wastewater directly into an aquifer, but the
quality of the aquifer, its status as an underground source of drinking water, and the resulting
impacts, are unknown.
Aquaculture wells generally are not vulnerable to spills or illicit discharges. Most are located
within private facilities and are not accessible to the public for unsupervised waste disposal.
However, the potential exists for operators to dispose of harmful liquid wastes (e.g., waste
aquaculture chemicals) via aquaculture injection wells. No such cases have been reported.
A total of 56 documented Class V aquaculture waste disposal wells exist in the United States. In
addition to these documented wells, as many as 50 additional wells are estimated to exist in CA.
Thus, the true number of aquaculture waste disposal wells in the United States is likely to
approach 100. Given that the value of aquaculture production has grown by 5 to 10 percent per
year over the past decade, and that the aquaculture industry remains the fastest growing segment of
United States agriculture, there is some possibility that the number of these wells will increase.
The great majority of the documented wells are located in HI (51 wells, or 93 percent). The
remaining documented wells are in WY (2), ID (1), NY (1), and MD (1).
Permit by rule: ID (for wells <18 feet deep), NY
Individual permit. HI, MD, ID (for wells >18 feet deep)
General permit: WY
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:
l no re e n. a l lib e rV/e pa. go The complete Class VUIC Study (EPA/816-R-99-014, September
1999), which includes a volume addressing aquaculture waste disposal wells (Volume 11), can be
found at http://www.epa.gov/OGWDW/uic/cl5study.html.

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