SWPPP Requirements in Maryland

Who needs a SWPPP in Maryland?

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 Maryland permit MDRC0000.

Maryland runs its own delegated stormwater program. Operators obtain coverage from Maryland Department of the Environment (MDE), Water and Science Administration under General Permit for Stormwater Discharge Associated with Construction Activity (20-CP) (MDRC0000), not directly from the EPA. A small subdivision, a solar pad, and a road-widening project all clear the same one-acre line.

Maryland adds requirements worth flagging early: Obtain approval of the Erosion and Sediment Control (E&SC) plan and the Stormwater Management (SWM) plan from the appropriate approval authority before construction; submit proof of E&SC approval with the NOI, and comply with the approved plans (20-CP Parts II.A.4.a, II.B.1, and III.A.2); A SWPPP under Part III.F is required only where chemical additives or polymers are used, contaminated soils are disturbed, turbidity-benchmark dewatering applies, MDE requires additional controls, Part III.A.3 pollution prevention controls apply (except projects under 5 acres triggered only by building materials, revegetation fertilizer, or concrete washout), operators share permit functions, or E&SC/SWM plans are exempt (20-CP Part III.F.1); Submit the NOI at least 14 days before construction through the MDE eNOI tool; coverage follows a 14-day public notification period and MDE’s authorization letter (20-CP Parts II.A.5, II.A.9, II.B, II.C); Complete the Antidegradation Checklist (Appendix C) for discharges to Tier II waters (20-CP Part II.A.4.b); Post a notice of permit coverage with the project name, permittee, “General Permit for Stormwater Associated with Construction Activity”, and the authorization number near the site (20-CP Part III.C.8.a); Assemble a stormwater team with at least one member holding the responsible-personnel training certificate, and train team members on their permit duties before construction begins (20-CP Part III.E); Dewatering to Tier II or sediment-impaired waters: sample turbidity daily against the 150 NTU benchmark and report quarterly through ePermits (20-CP Part III.B.4).

What the plan must contain

A Maryland 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

Submit the NOI through MDE’s NPDES eNOI tool (ePermits) at least 14 days before construction, attaching proof of E&SC and SWM plan approval, the antidegradation checklist, and a SWPPP when Part III.F.1 requires one, and pay the application fee.

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

The permit allows 2 inspection schedules; the operator follows one and records the choice in this plan: (a) weekly schedule with storm inspections — inspect at least once every calendar week and within 24 hours (the same day the rainfall ends or the next day) after a storm producing 0.25 inch of rain or more within a 24-hour period (calendar weeks run Sunday to Saturday; for a multi-day storm producing 0.25 inch or more each day, inspect within 24 hours of the first day and within 24 hours after the end of the storm; rainfall from an on-site rain gauge or a representative weather station) (20-CP Part III.C.2.a); or (b) 4-business-day schedule — inspect at least once every 4 business days (20-CP Part III.C.2.b). Dewatering discharges subject to turbidity benchmarks (to Tier II or sediment-impaired waters) are inspected once each day they occur, while the routine schedule still applies to the rest of the site (20-CP Part III.C.3.b); document the selected option and communications with the inspector in the SWPPP or inspection records (20-CP Part III.C.2). Every inspection is dated and signed, and any failed control is corrected before the next storm.

How Maryland differs from the federal permit

Because Maryland 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