How to Complete a Stormwater Pollution Prevention Plan

A Stormwater Pollution Prevention Plan is a site-specific document that identifies potential sources of stormwater pollution on a construction site and describes the Best Management Practices (BMPs) that will be used to reduce or eliminate that pollution. It is required under the Clean Water Act for construction activities covered by the EPA Construction General Permit or an equivalent state permit.

The SWPPP must be prepared before construction begins, kept on-site throughout the project, updated whenever site conditions or BMPs change, and retained for at least three years after permit coverage ends. It is not submitted to the EPA—it is a site management document that must be available for inspection at any time.

Who needs one? Any operator disturbing one or more acres, or less than one acre if part of a larger common plan of development, must obtain permit coverage and maintain a SWPPP for the life of the project.

The first section establishes the identity and context of the project. It must cover all of the following:

Project & Site Identity

Project name, address, county, and NPDES or CGP tracking number. Dates for Notice of Intent (NOI) submission and, eventually, Notice of Termination (NOT).

Responsible Parties

All operators—entities with day-to-day or design control over the site—must be identified. At least one 24-hour emergency contact is required. Project managers and stormwater contacts should also be documented.

Construction Activity

A description of the nature, function, and major phases of construction, including estimated start and completion dates. A construction phase timeline showing planned activities and BMPs for each phase is strongly recommended.

Soils, Slopes & Drainage

Existing soil types and erosion potential, current vegetation, pre- and post-construction drainage patterns, and slope category. Estimated total site area and disturbed area in acres.

Receiving Waters

All water bodies that receive discharge from the site, directly or through a storm sewer. Note whether any receiving water is listed as impaired under Section 303(d) or subject to a TMDL—additional BMPs may be required. Discharge points (outfalls) must be identified and located on the site map.

Sensitive Areas

Wetlands, Waters of the US, specimen trees, unstable slopes, sinkholes, or other features on or near the site that require protection from disturbance.

Potential Pollution Sources

A checklist of all applicable pollution source categories on the site (fueling, concrete washout, waste, stockpiles, etc.). Sources identified here drive the Good Housekeeping BMP requirements in Section 3.

ESA & Historic Preservation

Operators must certify eligibility under one of the EPA CGP's four Endangered Species Act criteria and confirm compliance with the National Historic Preservation Act Section 106 process before permit coverage begins.

Applicable Programs

Any other federal, state, tribal, or local stormwater programs that apply to the project, such as an MS4 permit or local grading ordinance, and any design standards they impose.

This section documents the structural and vegetative BMPs that will control erosion and capture sediment before it leaves the site. The CGP organizes these into eight categories, each of which must be addressed:

Minimize Disturbed Area

Limit clearing and grading to the smallest footprint necessary. Preserve natural buffers and vegetation in areas not required for construction.

Phase Construction

Sequence work so that earlier areas can be stabilized before new areas are disturbed. The construction phase timeline from Section 1 supports this requirement.

Control Stormwater Flows

Check dams, perimeter berms, and earthen diversions that slow, divert, or redirect runoff away from disturbed areas toward sediment-trapping devices.

Stabilize Soils

The CGP requires temporary stabilization of any area idle for 14 days or more (7 days near impaired waters) and permanent stabilization within 14 days of final grading. Methods include seeding, mulching, and erosion control blankets.

Protect Slopes

Cut and fill slopes require additional protection from raindrop impact and sheet flow. Rolled erosion control products, slope drains, and interceptor swales are common measures.

Protect Storm Drain Inlets

All inlets on or adjacent to the site must be protected. Inlet filters, rock dams, and silt sacks are common measures. Inlet protection must be inspected and maintained regularly.

Establish Perimeter Controls

A continuous perimeter barrier—silt fence, fiber rolls, compost berms, sediment traps, or basins—must surround the disturbed area. Vegetated buffers adjacent to water bodies must be maintained wherever practicable.

Retain Sediment On-site

Stabilized construction entrances at all vehicle exit points prevent trackout. Dewatering discharges must be filtered before leaving the site.

Each BMP entry should identify the BMP type, location, dimensions or design specifications, installation timing, and maintenance requirements.

For each pollution source identified in Section 1, this section must document where on the site that activity occurs, what pollutants it could generate, and the specific practices used to prevent contamination of stormwater runoff. Common source categories include:

• Material delivery & storage — covered storage, secondary containment for liquids, original containers with lids secured
• Fueling operations — designated fueling area away from drains and water bodies, spill kits, spill response procedures
• Vehicle & equipment maintenance — drip pans, impervious surfaces, proper collection and disposal of spent fluids
• Equipment washing — contained wash water, wheel wash stations near site exits
• Concrete washout — impermeable liner or prefabricated washout container, no discharge near storm drains or waterways
• Solid waste management — covered containers, regular collection, no accumulation in areas prone to runoff
• Sanitary waste — portable toilets secured and positioned away from drainage channels
• Stockpiles — surrounded by silt fence or berms, covered or seeded when inactive, located away from drainage channels
• Dewatering — discharge routed to a sediment trap or filter bag before leaving the site
• Dust control — water application, surface roughening, or temporary seeding; avoid chemical suppressants near water bodies

Identify any permanent stormwater management controls that will remain in place after construction is complete. These may be required by state or local programs in addition to the CGP. Common examples include infiltration basins, bioretention cells, detention ponds, permeable pavement, and vegetated swales.

For each control, document the type, location, design capacity, and maintenance responsibility after project closeout.

The CGP requires routine inspections at least every seven calendar days, or at least once every 14 days and within 24 hours of a storm event that produces 0.25 inches or more of rainfall. The SWPPP must document:

• The inspection schedule and any site-specific adjustments
• Inspector qualifications — who is authorized to perform inspections
• Scope of inspections — what areas and BMPs are checked each time
• How findings are recorded and corrective actions tracked

Inspection reports must be completed within 24 hours of the inspection and kept as part of the SWPPP record.

The SWPPP must describe both the training program for site personnel and the procedures for maintaining the required records.

Training

Who receives training, what topics are covered (BMP installation, maintenance, spill response), and how training is documented. Personnel responsible for implementing stormwater controls must be trained before they begin that work.

Recordkeeping

How inspection reports, BMP maintenance logs, training records, and any corrective action documentation are stored and for how long. The CGP requires records be retained for at least three years after permit coverage ends.

Final stabilization is achieved when all ground surface disturbing activities are complete and a uniform perennial vegetative cover with a density of at least 70% has been established on all unpaved areas, or equivalent permanent stabilization measures (riprap, pavement, structure) have been employed.

The SWPPP must track each disturbed area separately, documenting:

• Stabilization method used
• Date stabilization was achieved
• Area (acreage) stabilized

Once all areas are finally stabilized and all temporary controls have been removed, the operator can submit a Notice of Termination to end permit coverage.

All operators must sign the SWPPP certification statement, which affirms that the plan was prepared in accordance with applicable permit requirements and good engineering practices. The CGP requires the certification to be signed by a person with the appropriate level of authority (e.g., a responsible corporate officer, a general partner, or an authorized representative).

The SWPPP must be re-certified whenever it is amended. Each signatory's name, title, organization, and date of signature must be recorded.

A site map (or set of maps) must be included with the SWPPP showing the locations of all BMPs, drainage features, discharge points, sensitive areas, and the project boundary. Maps should be updated whenever BMPs are added, removed, or relocated. Many state permitting authorities require maps to be drawn to scale and to include a north arrow, legend, and revision history.

A SWPPP is a living document. It must be amended whenever:

• A new operator joins the project
• Site conditions change in a way that affects stormwater discharges
• An inspection identifies a BMP that is not functioning as designed
• A discharge causes or contributes to a water quality standard violation
• Construction plans change significantly

Amendments must be dated and the reason for the change documented. The SWPPP must always reflect current site conditions.