Regulatory Change – IDEM Transitioning from Rule 6 to Industrial Stormwater General Permit (ISGP)
IDEM issued the final Industrial Stormwater General Permit (ISGP) on December 30, 2025. This permit will replace the permit-by-rule codified in 327 IAC 15-6 (“Rule 6”) which has been the stormwater permit in Indiana for the last 20+ years. IDEM has not yet provided the Notice of Intent (NOI) form/mechanism [...]











