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The NPDES Permitting Program

The NPDES Permit Program is another regulatory program created through the Clean Water Act, and it is one of the main driving forces behind the majority of the mandated state and federal regulations. Under the NPDES Permit Program, stormwater discharges are considered point sources and operators of these sources are required to receive an NPDES permit before they can discharge stormwater runoff.

This NPDES Program as it relates to stormwater management was designed to be a phased control approach that begun in 1990. Once again, the EPA was responsible to develop, implement, and enforce regulations that would accomplish this task.

The EPA has successfully implemented Phase I and Phase II of this program and any new or modified regulations must go through a rulemaking process that includes a proposal, public comment, and then culminating with a final rule that must then be implemented and enforced. In addition to the above, the EPA has granted authority to allow states to implement the NPDES stormwater program.

State Regulation

State Regulations

Click here to learn more about the various State Regulations concerning Stormwater Management

EPA Regulations

Local Regulations

Click here to learn more about the various Stormwater Ordinances through local governments.

Federal Acts

The Clean Water Act

Click here to learn more about the Clean Water Act and how it impacts NPDES Stormwater permitting.


Phase I (1990)

Construction Activities

Required all construction sites disturbing 5 or more acres to obtain coverage to discharge stormwater under the NPDES Program.


Defined 11 categories of industrial activity (including construction) if disturbance of activity is equal to 5 acres or more than NPDES approval was required.


Required all municipalities with populations equal to 100,000 or more to acquire coverage for NPS discharge under the NPDES Program.


Phase II (March 2003)

Construction Activities

Required all construction sites disturbing 1-5 acres to acquire coverage under NPDES program.


Added 1-5 acres in Industrial activities and expanded upon the no exposure limitation from 1 group of activity to all 11 groups.


Required municipalities with populations between 10,000 and 100,000 to obtain NPDES Coverage.



Bureau of Water . Phone: (803) 898-4300 . Fax: (803) 898-3795 .