AZPDES Industrial Stormwater Multi-Sector General Permit (MSGP)
Industrial Stormwater Multi-Sector General Permit (MSGP)
Industrial stormwater permitting is an important part of the federal Clean Water Act and the State Surface Water Protection Program law to ensure surface water quality. Certain industrial activities are required to obtain permit coverage in order to discharge stormwater to protected surface waters. Unlike wastewater that is treated before being discharged to protected surface waters, stormwater does not get treated. The stormwater program relies on best management practices to minimize pollutants in stormwater discharges. ADEQ issues the industrial stormwater MSGP in Arizona. The MSGP identifies 29 different sectors that are subject to permitting for industrial stormwater discharges to protected surface waters | View Sector List >
A facility must have permit coverage if an industrial activity falls within one of the sectors and will discharge stormwater to protected surface waters. If industrial stormwater will not discharge to protected surface waters, either directly or by way of a conveyance (such as a street, ditch, etc.), stormwater permit coverage is not required | View Discharge FAQs >
If a facility would otherwise be regulated by the MSGP, but are exempt from the requirement to obtain a permit because there is no exposure of industrial materials or activities to precipitation or runoff because the industrial materials and activities at the site are covered by a storm-resistant shelter, you may apply for a No Exposure Certification | View No Exposure FAQs >
2019 Industrial Stormwater MSGP - Modified
The 2019 Industrial Stormwater MSGP replaced ADEQ’s 2010 Industrial Stormwater MSGP. The 2019 MSGPs were modified to include non-WOTUS protected surface waters. This modification was necessary in order to incorporate Arizona’s new Surface Water Protection Program (SWPP)1 | Visit SWPP Page >
The MSGP permit modifications became effective Sept. 29, 2021. No action is currently required to maintain coverage if you have an active NOI.