Understanding
Underground Injection Control
Technology
Safe Water Disposal Deep Undergound
What is Underground Injection Control (UIC)?
UIC is the process of disposing of non-hazardous, pre-treated wastewater and municipal stormwater — which would otherwise be released into surface water bodies like lakes, streams and rivers — and placing it deep underground into geologic formations for safe, secure and permanent disposal.
Who Regulates
UIC Wells?
Both the Florida Department of Environmental Protection (DEP) and the United States Environmental Protection Agency (EPA) have important roles to play in the oversight of UIC wells.
Regulators only authorize UIC wells when other wastewater disposal methods are not possible.
Florida law prohibits hazardous wastewater from being pumped underground.
Only pre-treated, non-hazardous water can be disposed underground and only in locations where geologic rock formations can naturally confine pre-treated water. State and Federal regulators agree that UIC is one of the most important technologies to help protect Florida’s streams and rivers.
Regulations require UIC wells to be continually monitored and tested to ensure structural integrity every 5 years.
The EPA sets the standards for the federal Underground Injection Control program in order to protect aquifers and underground sources of drinking water. They work with state environmental agencies to verify compliance with strict water quality standards.
As the state’s lead agency for environmental management and stewardship, DEP’s geologists and engineers administer and oversee the UIC program in Florida. DEP enforces strict standards for well installation and operation designed to ensure Florida’s drinking water remains pure and safe to drink.
Who Uses UIC In Florida?
Many municipalities and industries already use UIC technology! UIC is a readily available technology that municipalities use to better manage their water and protect local lakes, rivers and streams.
In fact, UIC wells are commonplace in the Sunshine State. There are 231 active deep injection wells in use in Florida today.
Common Types of UIC Wells:
Protecting Water Quality & Conserving Natural Resources
Class I
Municipal and industrial pre-treated water disposal
Class V
Exploratory wells, aquifer storage or recharge and stormwater runoff.
1960s
UIC first used in Florida
231
Class I UIC Systems in Florida
How Deep are The Wells?
It depends! The location, type of well, and quality of water being pumped all affect a well’s target injection zone.
Importantly, all underground disposal occurs deep beneath drinking water sources and is separated by thick, impermeable layers of rock.
Monitoring wells continually perform water quality sampling and verify that underground disposal remains controlled.
How Deep?
2,400 feet to 6,000 feet below sea level
Where Does the Water Go?
An essential regulatory requirement for UIC wells is to demonstrate that the geology of the underground injection location is isolated and that water will not reach the surface or the underground drinking water supply.
Monitoring wells are a requirement to confirm pumped water remains confined.
Most of the water already contained in the disposal zone is tens of thousands of years old — a relic from ancient geologic eras.
Once non-hazardous pre-treated water is injected into the formation, it remains there.
The rate of movement depends on a lot of factors, including the density of the rock, but it is typically in the “10’s of feet” per year range.
Over a geologic time scale (many thousands or tens of thousands of years) filtration through limestone will further clean disposed water