Stormwater best management practices (BMPs) are the primary tools for preventing polluted runoff from reaching waterways. The Clean Water Act, through the National Pollutant Discharge Elimination System (NPDES) permit program, requires facilities with industrial activities, construction sites disturbing one or more acres, and municipal separate storm sewer systems (MS4s) to implement and maintain stormwater BMPs as documented in a Stormwater Pollution Prevention Plan (SWPPP). Regular inspections verify that BMPs are properly installed, maintained, and effective at controlling pollutant discharge. Failures identified during EPA or state inspections can result in significant penalties under the Clean Water Act. This guide covers all inspection requirements with a free downloadable checklist.
Free Stormwater BMP Inspection Checklist
Download our Word document checklist covering erosion controls, sediment management, outfall monitoring, and good housekeeping BMPs per NPDES requirements.
Download Checklist (.docx)Regulatory Framework
Clean Water Act & NPDES Program
- Clean Water Act §402: Establishes the NPDES permitting program. Prohibits discharge of pollutants from point sources to waters of the United States without a permit. Stormwater discharges from industrial, construction, and municipal sources require NPDES permit coverage.
- Multi-Sector General Permit (MSGP): EPA’s general permit for stormwater discharges from industrial activities. Requires quarterly visual assessments of stormwater discharge, annual comprehensive site compliance evaluations, benchmark monitoring for specific sectors, and a current SWPPP.
- Construction General Permit (CGP): Covers construction sites disturbing one or more acres. Requires inspections every 7 days or every 14 days plus within 24 hours of a 0.25-inch rain event. SWPPP must be developed before construction begins.
- State permits: Most states are authorized to administer their own NPDES stormwater programs and may impose additional or stricter requirements than the federal permits. Always verify state-specific requirements.
SWPPP Requirements
- Pollution Prevention Team: Identify individuals responsible for developing, implementing, and maintaining the SWPPP.
- Site Description: Facility map showing buildings, storage areas, drainage patterns, outfall locations, structural BMPs, and receiving waters.
- BMP Selection: Document all structural and non-structural BMPs for erosion control, sediment management, good housekeeping, and post-construction runoff management.
- Inspection & Monitoring: Establish inspection schedules, monitoring protocols, and record-keeping procedures. Retain records for the permit term plus 3 years.
Clean Water Act penalties: Violations of NPDES permit conditions can result in civil penalties up to $64,618 per day per violation. Criminal penalties for negligent violations include fines up to $50,000 per day and up to one year imprisonment. Citizen suit provisions allow third parties to bring enforcement actions against non-compliant facilities.
Part 1: Erosion & Sediment Controls
| Inspection Item | What to Check |
|---|---|
| Silt fences | Silt fence fabric intact with no tears, gaps, or undermining. Posts firmly anchored and not leaning. Bottom of fabric properly trenched or keyed into soil. Sediment accumulation not exceeding one-third of fence height. No bypass flow around fence ends. Fence positioned on contour (not down-slope). |
| Sediment basins/traps | Basin not exceeding 50% sediment capacity (clean out when 50% full). Outlet structure and dewatering device functioning properly. Embankment stable with no erosion, seepage, or animal burrows. Emergency spillway clear and unobstructed. No visible oil sheen or unusual discoloration on standing water. |
| Inlet protection | Storm drain inlet protection (filter fabric, gravel bags, or manufactured devices) in place and functioning. No bypass flow around inlet protection. Sediment accumulation not blocking more than 25% of inlet capacity. Protection devices securely anchored and not displaced by flow. |
| Stabilized entrances | Construction entrance/exit stabilized with aggregate or paving. Aggregate thickness and dimensions per SWPPP specifications. No sediment tracking onto public roads. Tire wash station functioning (if required). Entrance draining back into the site, not onto public roadway. |
| Slope stabilization | Temporary and permanent seeding/mulching applied to disturbed areas per SWPPP schedule. Erosion blankets and turf reinforcement mats properly anchored. No rills, gullies, or concentrated flow channels forming. Diversion channels and berms directing runoff to sediment controls. Soil stockpiles properly covered or contained. |
Part 2: Good Housekeeping & Material Management
| Inspection Item | What to Check |
|---|---|
| Material storage | Chemicals, fuels, and raw materials stored in covered areas or under tarps per SWPPP. Secondary containment provided for liquid materials. Containers in good condition with lids closed. No evidence of leaks or spills. Materials stored away from storm drains and drainage pathways. |
| Waste management | Dumpsters and waste containers closed and covered. No overflowing containers. Construction debris contained and not blocking drainage pathways. Wash-out areas (concrete, paint) properly contained and away from storm drains. Waste disposal documentation current. |
| Vehicle and equipment areas | Designated fueling and maintenance areas with appropriate spill prevention controls. Drip pans under leaking equipment. No visible oil, grease, or fuel stains on ground surface. Vehicle wash areas directed to proper treatment or sanitary sewer (not storm drain). |
| Outfall monitoring | All identified outfalls accessible and observable. No unauthorized discharges. No visible oil sheen, discoloration, foam, or odor in discharge. Outfall structures (pipes, headwalls, riprap) in good condition. Quarterly visual assessment documented per MSGP requirements. |
| Spill prevention | Spill kits available near material storage and fueling areas. Spill response plan posted or accessible. Employees trained in spill cleanup procedures. Spill history log current. Any recent spills properly cleaned up with no residual contamination. |
Part 3: Structural BMPs & Post-Construction Controls
| Inspection Item | What to Check |
|---|---|
| Detention/retention ponds | Pond embankment stable with no erosion, cracking, or settlement. Outlet control structure functioning properly and not clogged. Trash racks and screens clear of debris. Vegetation maintained (mowed, no invasive species). Sediment accumulation not reducing design capacity below acceptable levels. No evidence of mosquito breeding (stagnant water maintenance). |
| Bioswales and vegetated channels | Channel cross-section maintained to design dimensions. Vegetation healthy and providing adequate coverage. No concentrated flow bypassing treatment area. Inlet and outlet structures functioning. Check dams intact and properly spaced. No sediment accumulation impeding flow or reducing treatment volume. |
| Infiltration practices | Infiltration basin/trench draining within design drawdown time (typically 48–72 hours). No standing water beyond design retention period. Pretreatment structures (forebays, filter strips) functioning. Surface not clogged or compacted. Observation wells (if present) showing proper infiltration rates. |
| Manufactured treatment devices | Hydrodynamic separators, filter cartridges, and media filters inspected per manufacturer schedule. No bypass occurring during design storm events. Cartridges/media replaced at required intervals. Sediment and pollutant accumulation within acceptable limits. Maintenance access clear and unobstructed. |
| Conveyance systems | Drainage channels, ditches, and swales free of blockages and debris. Pipe inlets and outlets clear. Riprap and outlet protection stable and not displaced. No evidence of erosion, scour, or undercutting. Culverts flowing freely without ponding at inlet. Energy dissipaters functioning at discharge points. |
Inspection frequency summary: Industrial facilities (MSGP): quarterly visual assessments of discharge plus annual comprehensive site compliance evaluation. Construction sites (CGP): every 7 days, or every 14 days plus within 24 hours of 0.25-inch rain event. Post-construction BMPs: per local MS4 permit requirements, typically annually or semi-annually. All inspections must be documented with inspector name, date, weather conditions, findings, and corrective actions. Records must be retained for the permit term plus 3 years minimum.
Download the Free Checklist
Get our stormwater BMP inspection checklist in Word format. Covers erosion controls, housekeeping BMPs, structural controls, and documentation.
Download Checklist (.docx)Go digital with Ecesis. Manage stormwater BMP inspections across all your sites with Ecesis inspection software. Document BMP conditions with timestamped GPS-tagged photos. Track corrective actions through completion. Generate NPDES-ready inspection reports. Integrate with your SWPPP and SPCC programs. Request a free demo.
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Training
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