Office of
United States	Ground Water and
Environmental Protection Agency	Drinking Water
What is a salt water intrusion	Salt water intrusion barrier wells are Class V underground injection control (UIC)
barrier well?	wells used to inject water into a fresh water aquifer to prevent the intrusion of salt
water. These wells may have secondary purposes, such as to recharge an aquifer with
fresh water to be used later or to control land subsidence (reduce ground movement).
What types of fluids are injected
Waters of varying qualities are injected to create salt water intrusion barriers.
into salt water intrusion barrier
including untreated surface water, treated drinking water, and mixtures of treated
municipal wastewater and ground or surface water.
Do injectate constituents exceed
Available data show that the injectate typically meets primary and secondary drinking
drinking water standards at the
water standards and health advisory levels at the point of injection.
point of injection?

What are the characteristics of the
Salt water intrusion barrier wells are drilled to various depths depending on the depth
injection zone of salt water intrusion
of the aquifer being protected. They inject into fresh ground water aquifers used as
barrier wells?
drinking water supplies that are in hydraulic connection with an extensive salt water

body, such as a sea, a salt lake, or an ocean.
Are there any contamination
No contamination incidents associated with the operation of salt water intrusion
incidents associated with salt water
barrier wells have been reported.
intrusion barrier wells?

Are salt water intrusion barrier
Because protection of drinking water supplies is the major goal of a salt water
wells vulnerable to spills or illicit
intrusion barrier well and the injectate typically meets drinking water standards, salt
water intrusion barrier wells are unlikely to receive spills or illicit discharges of

potentially harmful substances.
How many salt water intrusion
There are 315 salt water intrusion barrier wells documented in the United States. The
barrier wells exist in the United
number of salt water intrusion barrier wells in the nation is estimated to be greater
than 609, but unlikely to be higher than 700.
Where are salt water intrusion
All documented salt water intrusion barrier wells are located in CA (308), FL (1), and
barrier wells located within the
WA (6). In addition, as many as 200 salt water intrusion barrier wells are believed to
United States?
exist in NY. There also may be some wells in NJ; however, the exact number of such

wells in this state is unknown.
How are salt water intrusion barrier
Permit bv rule: CA
wells regulated in states with the

largest number of this type of well?
Individual permit. FL, NY, and WA
Where can I obtain additional
For general information, contact the Safe Drinking Water Hotline, toll-free 800-426-
information on salt water intrusion
4791. The Safe Drinking Water Hotline is open Monday through Friday, excluding
barrier wells?
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: moreen.amber@epa.gov.
The complete Class VUIC Study (EPA/816-R-99-014, September 1999), which
includes a volume addressing salt water intrusion barrier wells (Volume 20), can be
found at http://www.epa.gov/OGWDW/uic/cl5study.html.