SWPPP Requirements in Mississippi

Who needs a SWPPP in Mississippi?

Any construction project that disturbs one acre or more — or is part of a larger common plan of development reaching one acre — needs a SWPPP under Mississippi permit MSR10 (large construction general permit, 5 acres or more (msr10)), MSR15 (small construction general permit, or 1 to under 5 acres (msr15)).

Mississippi runs its own delegated stormwater program. Operators obtain coverage from MDEQ under Large Construction Storm Water General Permit (MSR10 / MSR15), not directly from the EPA. A small subdivision, a solar pad, and a road-widening project all clear the same one-acre line.

Mississippi adds requirements worth flagging early: Submit the Large Construction Notice of Intent (LCNOI) with the site-specific SWPPP and a USGS quad map extending at least 1/2 mile beyond the property; discharge only after written notification of coverage from MDEQ (ACT3 S-1, ACT4 S-1 and S-2) (MSR10); Design controls to the current Mississippi "Erosion Control, Sediment Control and Stormwater Management on Construction Sites and Urban Areas" manual or another approved design manual (ACT5 T-4) (MSR10); Sediment basin of at least 3,600 cubic feet per acre drained, installed before initial grading, for drainage locations serving 10 or more disturbed acres at one time (not required for linear projects) (ACT5 T-6(A)–(B)) (MSR10); Phase construction to keep total disturbance under 50 acres at one time unless justified with additional controls (ACT5 T-8(H)) (MSR10); Written justification in the SWPPP for any required control deemed infeasible (ACT5 T-2, T-5, T-8) (MSR10); Stormwater team training before construction, documented on the training log (ACT5 T-20, T-21) (MSR10); Submit the Major Modification Form for subsequent phases, expansions, and modifications not in the original SWPPP (ACT6 S-2(7)) (MSR10); Submit a Request for Termination with color photographs within 30 days of final stabilization (ACT10 S-1) (MSR10); Complete the Small Construction Notice of Intent (SCNOI) before construction and keep it with the SWPPP on site; submit it (electronically) only when MDEQ requests it, and then discharge only after written approval (ACT3 S-1, ACT4 S-1 and T-1) (MSR15); Document every inspection on the MDEQ Inspection and Certification Form, including the day and time, inspector, deficiencies, and corrective action, and keep it with the SWPPP (ACT8 R-2) (MSR15); Written justification in the SWPPP for any required control deemed infeasible (ACT5 T-1, T-3) (MSR15); Record the completion date of all permanent erosion and sediment controls on the final inspection report (ACT9 S-1) (MSR15).

What the plan must contain

A Mississippi SWPPPis the site's compliance binder — the document an inspector opens first. It documents:

1. 1Site & project descriptionTotal and disturbed acreage, soils, slopes, and the sequence of construction.
2. 2Receiving waters & discharge pointsWhere stormwater leaves the site and the waterbodies it reaches.
3. 3Erosion & sediment control BMPsSilt fence, stabilized entrances, inlet protection, and stabilization measures.
4. 4Inspection schedule & recordsDated, signed inspection logs and the corrective actions taken.
5. 5Operator certificationThe SWPPP is signed by the legally responsible party before work begins.

Required and conditional BMPs

Filing your Notice of Intent

5 acres or more (MSR10): submit the LCNOI with the SWPPP and USGS quad map to MDEQ electronically (required after 2025-12-21) and wait for written coverage. 1 to under 5 acres (MSR15): complete the SCNOI and SWPPP before construction and keep them on site; submit only if MDEQ requests.

A Notice of Termination closes coverage once the site reaches final stabilization. Keeping the SWPPP and its inspection records on site is what keeps a project clear of stop-work orders.

Inspection requirements

Inspect at least once every calendar week and after rain events that produce a discharge (a minimum of four inspections per month, and as often as is necessary to ensure that appropriate erosion and sediment controls have been properly constructed and maintained and to determine if additional or alternative control measures are required) (MSR10 ACT5 T-16 and ACT6 S-5). Inspections use the MDEQ inspection form (or equivalent) and are performed by qualified personnel; MDEQ strongly recommends a daily walk-through inspection (MSR10 ACT6 S-5). Every inspection is dated and signed, and any failed control is corrected before the next storm.

How Mississippi differs from the federal permit

Because Mississippi administers its own program, the federal EPA Construction General Permit does not apply directly here — the state permit governs. Sites inside a regulated municipal storm sewer system may carry additional local ordinance requirements on top of the state permit.

Frequently asked questions