The state operates under the Mississippi Storm Water Program, regulated through the Mississippi NPDES MS4 Permit (Permit No. MSRMS4), and the voluntary state-wide Stormwater Guidance Manuals. Guidance manuals throughout the state were created individually by Phase I MS4s and a group of 19 Phase II municipalities. The state has no numerical standards for post-construction, however the individual MS4s must meet a maintenance and good housekeeping requirement. The general permit and Mississippi Handbook for Construction Sites and Urban Areas are available online.