Department of
Environmental Quality

The NPDES program requires facilities discharging from a point source into waters of the U.S. to obtain discharge permits. (A point source is a conveyance such as a pipe or other point.) An NPDES permit contains limits on what can be discharged and other provisions to ensure that the discharge does not harm water quality or the public's health.

There are two basic types of NPDES permits:

• An individual permit is a permit written specifically for an individual facility.
  
• A general permit may cover multiple facilities within one industry, such as aquaculture, or may cover multiple facilities from different industries but that have a similar discharge, such as storm water. General permits are only issued to dischargers within a specific geographical area.

NPDES Program Oversight in Idaho

In Idaho, the NPDES permit program is administered by EPA, which means EPA is responsible for issuing and enforcing all NPDES permits in Idaho. Idaho is one of only a handful of states where the NPDES program is administered by EPA. States are encouraged by EPA to attain primacy for the program. Primacy enables states to assume responsibility for administering certain federally mandated programs, such as the NPDES program. Over the past several years, various studies have been conducted on the pros and cons of transferring primacy for the NPDES program from EPA to DEQ. Several reports have been submitted to the Legislature outlining the benefits of doing so, but questions remain over potential costs and funding. As a result, responsibility for operating the program in Idaho continues to rest with EPA.

The state's role in this process is to certify that NPDES-permitted projects comply with state water quality standards. EPA typically provides a preliminary draft NPDES permit for DEQ to review and develop a draft certification. In order to streamline the public comment process, EPA will generally issue a joint public notice indicating the draft permit and certification are available for public comment. To facilitate review, EPA will generally append the draft certification to the fact sheet. However, DEQ may request public comment directly for general permits or individual permits for particularly large or sensitive projects. After the public comment period has ended, EPA provides DEQ with a proposed final permit for certification and generally requests DEQ provide a final certification decision within 30 days. EPA may provide a longer period of time to issue a certification decision in some cases. Learn more about the certification process.

Aquaculture Facilities

Aquaculture is the cultivating of freshwater fish, such as salmon and trout, under controlled conditions for commercial, conservation, and recreation uses. EPA has issued a general NPDES permit for aquaculture facilities and associated fish processing facilities in Idaho. Learn more.

Concentrated Animal Feeding Operations (CAFOs)

The Clean Water Act defines concentrated animal feeding operations, also called "CAFOs" or "feedlots," as point sources; therefore, they are subject to NPDES permitting. Animal waste and wastewater can enter water bodies from spills or breaks of waste storage structures and non-agricultural application of manure to crop land. EPA has proposed a general NPDES permit for CAFOs in Idaho. Learn more.

Wastewater Treatment Plants

Wastewater treatment plants collect wastewater (mainly domestic sewage) and may discharge treated wastewater into waters of the Unites States with an NPDES permit. The permits include provisions relating to biosolids; permits for municipal facilities may also specify pretreatment requirements for industries that discharge their wastewater to the wastewater treatment plants. EPA uses the term "publicly owned treatment works" to describe municipal wastewater treatment plants.

Biosolids (Sewage Sludge)

Biosolids are the nutrient-rich organic materials resulting from the treatment of sewage sludge (the solid, semisolid, or liquid untreated residue generated during the treatment of domestic wastewater [sewage]). Biosolids can be safely recycled and applied as fertilizer.

A biosolids permit is required for wastewater treatment plants that treat domestic sewage and is issued as part of the facility's NPDES permit. Other types of industries may work with biosolids or apply biosolids as fertilizer and may not be required to obtain a biosolids permit (always check with EPA to be sure). However, those who work with biosolids must comply with federal biosolids regulations even when a permit is not required.

In addition to federal regulations, Idaho has its own state rules that regulate the use of sewage sludge (biosolids) (IDAPA 58.01.02.650, Sludge Usage). These rules require land appliers of domestic sewage sludge to submit a sludge disposal plan to DEQ or obtain approval on a site-by-site basis. DEQ must approve the plan before the sludge can be land applied.

Pretreatment

The National Pretreatment Program is a portion of the NPDES program established to address discharges from industries to wastewater treatment plants. The program requires industrial and commercial dischargers to treat ("pretreat") or control pollutants in their wastewater prior to discharge to wastewater treatment plants. It is the wastewater treatment plant's NPDES permit that specifies pretreatment requirements. Industrial users must comply with the pretreatment standards and reporting requirements.

Stormwater

Stormwater is water from rain or melting snow that does not immediately soak into the ground. Stormwater runs off of land and hard surfaces such as streets, parking lots, and rooftops, and picks up pollutants, such as fertilizers, dirt, pesticides, and oil and grease. Eventually, stormwater soaks into the ground or discharges to surface water (usually through storm drains), bringing the pollutants with it. Most stormwater discharges are considered point sources and require coverage by an NPDES permit. Construction activities, certain industries, and municipal separate storm sewer systems (MS4s) are all required to have stormwater permits. Like the rest of the NPDES program, the NPDES stormwater program in Idaho is operated by EPA. Learn more.