SWPPP glossary: stormwater compliance terms, defined
Construction stormwater compliance runs on acronyms. These are the terms that show up in permits, SWPPPs, inspection forms, and enforcement letters — defined in plain English, with the federal EPA 2022 Construction General Permit as the baseline (state permits vary; see requirements by state).
SWPPP (Stormwater Pollution Prevention Plan)
The site-specific plan required by construction stormwater permits, documenting the erosion and sediment controls a site will use, who is responsible, and how the site will be inspected and maintained. Pronounced "swip." Must be written before the NOI is filed and kept current and accessible for the life of the project.
CWA (Clean Water Act)
The federal law making it illegal to discharge pollutants into waters of the United States without a permit. Sediment leaving a construction site in stormwater is legally a pollutant discharge under the CWA.
NPDES (National Pollutant Discharge Elimination System)
The permitting system created by Clean Water Act Section 402. EPA administers it directly in a few states; delegated state agencies (TCEQ, GA EPD, etc.) run it everywhere else.
CGP (Construction General Permit)
The general NPDES permit covering construction stormwater discharges. Operators get coverage by filing a Notice of Intent rather than negotiating individual permits. EPA's current version is the 2022 CGP; delegated states issue their own equivalents (TXR150000 in Texas, GAR100002 in Georgia, and so on).
NOI (Notice of Intent)
The filing that requests coverage under a general permit. Under the federal CGP it is submitted electronically at least 14 calendar days before construction begins, and a SWPPP must exist before it is filed.
NOT (Notice of Termination)
The filing that ends permit coverage once a site reaches final stabilization. Inspection and corrective action records must be retained for at least 3 years after the NOT.
Operator
Any party with operational control over construction plans and specifications or day-to-day site activities. On many projects both the owner/developer and the general contractor qualify — and each needs its own permit coverage.
BMP (Best Management Practice)
Any control measure used to prevent or reduce pollutant discharge: silt fence, inlet protection, stabilized construction entrances, sediment basins, concrete washouts, and the like. The SWPPP specifies which BMPs a site uses and where.
Qualifying rain event
A storm producing enough rain to trigger a post-storm inspection — 0.25 inches within 24 hours under the federal CGP, with state triggers ranging up to 1.0 inch. Cumulative totals across multiple showers count, and the inspection is generally due within 24 hours.
Rain gauge / representative weather data
The permit's two accepted ways to measure rainfall: an on-site gauge, or precipitation data from a source representative of the site's location. Some states (North Carolina, Georgia) specifically require an on-site gauge.
Qualified person
The federal CGP's standard for who may perform inspections: someone knowledgeable in erosion and sediment control principles who can assess site conditions and control effectiveness. Many states layer named certifications on top — QSP, CESCL, Blue Card, RLD.
Corrective action
The permit-mandated response when a control has failed, was never installed, was installed wrong, or a prohibited discharge occurred. Carries deadlines (next business day for simple fixes; 7 calendar days when a control must be replaced or significantly repaired) and must be logged within 24 hours of identification and completion.
Stabilization
Covering or vegetating disturbed soil so it no longer erodes — seeding, sod, mulch, blankets. Where work stops for 14 or more days, stabilization must be initiated immediately and completed within 7 or 14 calendar days depending on disturbed acreage. Final stabilization is the prerequisite for filing the NOT.
MS4 (Municipal Separate Storm Sewer System)
A publicly owned storm drainage system regulated under its own NPDES permit. Cities operating MS4s inspect construction sites that drain into their systems and can issue local fines and stop-work orders on top of state and federal enforcement.
Receiving water
The creek, river, lake, or wetland a site's stormwater ultimately drains to. Sites discharging to impaired or high-quality receiving waters face stricter inspection frequencies and buffer requirements under CGP Part 4.3.
Buffer zone
The undisturbed natural area the federal CGP requires between construction disturbance and nearby surface waters — 50 feet, or a documented equivalent sediment-control alternative.
Track-out
Sediment carried from the site onto public roads by vehicle tires. It is a discharge of pollutants that bypassed the site's controls, and one of the most commonly cited violations because it's visible from the street.
Dewatering
Pumping accumulated stormwater or groundwater out of excavations. Discharges must pass through sediment controls (filter bags, basins), and dewatering days require daily inspection of those controls.
Concrete washout
The contained area where concrete trucks and equipment rinse out. Washout water is highly alkaline and is a prohibited discharge if it reaches the ground or storm drains — every site pouring concrete needs a designated, maintained washout.
QSP / QSD (California)
Qualified SWPPP Practitioner and Qualified SWPPP Developer — California's mandatory credentials. The QSD writes and amends the SWPPP; the QSP implements it, oversees inspections and sampling, and executes Rain Event Action Plans.
CESSWI
Certified Erosion, Sediment and Storm Water Inspector — a national EnviroCert credential widely held by third-party stormwater inspectors and consultants.
CESCL (Washington)
Certified Erosion and Sediment Control Lead — the credential Washington's construction permit requires for site inspection personnel.
REAP (Rain Event Action Plan)
California-specific: a written plan required 48 hours before any forecast storm meeting the trigger, describing how the site will be secured ahead of the rain.
Audit binder
The complete, producible-on-demand record set for a site: the SWPPP, permit documents, every inspection report, rain log, and corrective action trail. The permit requires records to be kept on site or immediately accessible — RainCheck generates this as a single PDF in one click.
Common questions
How do you pronounce SWPPP?
"Swip" — one syllable. Occasionally spelled out as S-W-P-P-P in formal contexts, but nobody on a job site says it that way.
Is a SWPPP the same thing as an erosion control plan?
Not quite. An erosion and sediment control (ESC) plan is usually the engineering drawing set showing where controls go. The SWPPP contains that plus the stormwater team, inspection procedures, pollution prevention practices, stabilization deadlines, and eligibility documentation — the full compliance document the permit requires.
What's the difference between the NOI and the permit?
The Construction General Permit already exists as a standing set of terms. The NOI is your application to be covered under it. Once coverage is granted, your obligations are whatever the CGP says — the NOI itself is just the enrollment paperwork.