Department of
Environmental Quality

DEQ's Water Quality Division is responsible for assuring that the state's surface, ground, and drinking water resources meet state water quality standards.

Water Quality Standards

Idaho adopts water quality standards to protect public health and welfare, enhance the quality of water, and serve the purposes of the Clean Water Act. These standards are the benchmarks DEQ uses to know if it is doing its job to protect Idaho's surface water.

Any project that requires a federal permit or license under the Clean Water Act, such as a license to operate a hydroelectric dam, a National Pollutant Discharge Elimination System permit, or a Clean Water Act Section 404 dredge and fill permit, requires a Clean Water Act Section 401 certification. The certification states that the project will not cause a violation of state water quality standards.

Surface Water Quality

DEQ's Surface Water Program routinely measures and assesses the levels of pollutants in surface waters such as rivers and streams. The program develops analytical tools, provides guidance for stream and river water quality evaluations, monitors protocols and schedules, and writes and submits federally required reports. Regional office staff perform on-the-ground water quality testing and data collection.

When water quality fails to meet state water quality standards, regional office staff work with communities, industry, and citizen groups to develop water quality improvement plans known as total maximum daily loads (TMDLs). These plans outline the actions needed to restore impaired water bodies to a healthy fishable, swimmable condition. Surface Water staff coordinate the overall TMDL program; regional office staff develop and write the individual TMDLs.

The Nonpoint Source Management Program provides grants to states, territories, and tribes to support a wide variety of water quality improvement activities.

Safe Drinking Water

Working with public health districts, DEQ's Drinking Water Program assists public drinking water systems in complying with state requirements, conducts sampling surveys and on-site visits to prevent public health problems, reviews water system plans and specifications, conducts training sessions, publishes informational brochures and the quarterly Idaho Drinking Water Newsletter, and contracts for statewide operator training classes. DEQ also works with public water systems to assure that their systems are secure and prepared to respond to emergencies.

In addition, DEQ assesses potential contaminant threats to Idaho's drinking water sources. DEQ completed assessments on all recognized public water sources in May 2003; new sources are assessed as they come on-line. The completed source water assessments summarize the likelihood of individual drinking water sources becoming contaminated and serve as a foundation for public water systems to prepare drinking water protection plans and implement protection measures.

Ground Water Protection

More than 95% of the water used by Idaho households comes from ground water. DEQ is responsible for protecting the quality of ground water in Idaho and relies on a combination of programs to protect ground water from pollution, clean up degraded ground water, and monitor and assess ground water quality. DEQ's ground water policy is to maintain and protect the existing high quality of Idaho's ground water and restore degraded ground water where feasible to support beneficial uses.

Stormwater Management

Stormwater is water from rain or melting snow that does not immediately soak into the ground. Stormwater discharges are generated by runoff from land and impervious areas such as paved streets and parking lots and can contain pollutants in quantities that could adversely impact water quality. DEQ provides technical guidance for the selection and site design of stormwater best management practices to manage the quantity and quality of stormwater runoff.

On-Site Wastewater Systems (Septic Systems)

Households and commercial facilities that are not served by public sewer systems depend on on-site (decentralized) systems to treat and dispose of wastewater. DEQ has established minimum standards for the design, construction, siting, and use of these systems.

Wastewater Reuse Permits

Permits are designed to protect surface and groundwater resources by establishing limits on the amount of wastewater that facilities and industries may reuse as a regular part of their operations. Regional and state office staff develop wastewater reuse permits, provide technical assistance to facilities and industries, conduct inspections, and enforce permits as necessary to assure compliance with water quality standards.

Grants and Loans

Among the ways DEQ works to protect public health is by providing grants and low-interest loans to help public drinking water and wastewater systems plan, construct, update, and maintain their facilities. DEQ's Loan Program coordinates and oversees this effort.