Office of Water Quality Watershed Planning Branch
Wetland and Storm Water Section - Stormwater Water Quality Program
100 North Senate Avenue MC 65-42, Room 1255
Indianapolis, Indiana 46204
Indiana’s Stormwater permit is a "permit by rule" so it has no set expiration date.
327 IAC 15-6, Rule 6
(15) "Measurable storm event" means a precipitation event that results in a total measured precipitation accumulation equal to, or greater than, one-tenth (0.1) inch of rainfall.
(25) "Qualified storm event" means a discharge resulting from a measurable storm event at least seventy-two (72) hours after the previous measurable storm event. The term does not include discharges of snowmelt.
(9) All samples must be collected from a discharge resulting from a measurable storm event at least seventy-two (72) hours from the previous measurable storm event. Documentation of weather conditions that prevent sampling as described in this subsection must be provided to the commissioner.
Magnitude: 0.1 inch or greater
Interval Between Storms: at least 72 hours