4.1 SS Prerequisite: Construction Activity Pollution Prevention
Key Takeaways
- Construction Activity Pollution Prevention is a required SS Prerequisite worth zero points but mandatory for any LEED BD+C certification.
- The Erosion and Sedimentation Control (ESC) plan must conform to the 2017 EPA Construction General Permit (CGP) or a local equivalent if more stringent.
- Goals are to reduce pollution from soil erosion, prevent sedimentation of storm sewers and receiving streams, and prevent airborne dust generation.
- Sediment controls (silt fence, fiber rolls, inlet protection, stabilized entrances) capture material that has already eroded; erosion controls (mulching, blankets, vegetation, terracing) prevent erosion at the source.
- Documentation requires the ESC plan, narrative, drawings, photos of installed BMPs, and inspection logs even if the project is below the 1-acre CGP threshold.
Sustainable Sites (SS) is worth up to 10 points on the LEED BD+C v4/v4.1 New Construction scorecard, but before a project can earn any of them it must clear one mandatory gate: the Construction Activity Pollution Prevention prerequisite. This prerequisite is the foundation of the entire SS category and the most frequently missed item on real-world LEED submittals because it requires action before ground is broken, not at design review.
Why This Prerequisite Exists
Construction sites generate sediment loads 10 to 20 times greater than agricultural land and 1,000 to 2,000 times greater than forested land. Without controls, that sediment ends up in storm drains, streams, and wetlands, smothering aquatic habitat and clogging municipal infrastructure. The U.S. EPA estimates construction sites discharge 70 to 80 million tons of sediment into U.S. waters annually. LEED requires every project to interrupt this pipeline.
The Two Reference Standards
A project must implement an Erosion and Sedimentation Control (ESC) plan that conforms to one of the following, whichever is more stringent:
| Standard | Issued By | Scope |
|---|---|---|
| 2017 Construction General Permit (CGP) | U.S. EPA | Federal baseline for construction sites disturbing one or more acres |
| Local equivalent | State, county, or city stormwater authority | Applied when more protective than the EPA CGP |
Important exam fact: the LEED requirement applies regardless of project size. Even a project disturbing less than one acre, which would normally fall below the EPA CGP threshold, must still meet the CGP performance standards to earn this prerequisite.
Three Pollution Pathways the ESC Plan Must Address
The ESC plan must demonstrate how the project will address each of the following:
- Soil erosion — wind and water carrying soil off the disturbed site
- Waterway sedimentation — sediment reaching storm sewers and receiving waters
- Airborne dust — particulate matter from grading, demolition, and stockpiles
Sediment vs. Erosion Controls
LEED reviewers expect to see both categories on the plan. They are not interchangeable.
Sediment Control Devices (capture what has already eroded)
| BMP | Where Used | Typical Limit |
|---|---|---|
| Silt fence | Down-gradient perimeter | Sheet flow only; not concentrated flow |
| Fiber rolls / wattles | Slopes and around inlets | Spaced 10–25 ft apart on slopes |
| Stabilized construction entrance | Vehicle ingress/egress | 50 ft minimum length, 2–3 in. crushed stone |
| Inlet protection | Every active storm drain inlet | Required even on existing inlets receiving site runoff |
| Sediment basin / trap | Drainage areas ≥5 acres (basin) or <5 acres (trap) | 3,600 cu ft per acre drained per 2017 CGP |
Erosion Controls (prevent erosion at the source)
- Temporary and permanent seeding — fastest way to stabilize exposed soil; required within 14 days of stopping work on a portion of the site per the 2017 CGP
- Mulching, hydromulch, and erosion-control blankets — protect bare soil until vegetation establishes
- Terracing and slope roughening — break up long slopes; track-walking equipment perpendicular to the slope is a low-cost technique
- Preservation of existing vegetation — the cheapest erosion control on any site
- Diversion swales and check dams — reroute clean upslope runoff away from the disturbed area
Dewatering Practices
When groundwater or accumulated stormwater is pumped from excavations, the discharge cannot be released directly to a storm drain or waterway. Acceptable practices include:
- Discharging to a dewatering bag, sediment trap, or temporary sediment basin sized for the pump rate
- Using flocculants (e.g., chitosan, polyacrylamide) on highly turbid water
- Visual inspection at the outlet for turbidity before discharge
- Documenting all dewatering events in the construction log
Post-Construction Stormwater Management
The ESC plan is temporary; the project must transition to a permanent stormwater management strategy as construction wraps up. This typically aligns with the SS Credit: Rainwater Management (covered in 4.3) using bioswales, rain gardens, pervious pavement, green roofs, or detention.
Documentation Required for the Submittal
- The ESC plan narrative describing each BMP, sequencing, and inspection schedule
- A site plan showing BMP locations, drainage patterns, and limits of disturbance
- Inspection logs (the 2017 CGP requires inspections at least every 7 calendar days, plus within 24 hours of a 0.25-inch storm event)
- Date-stamped photographs of installed BMPs at the start, midpoint, and end of construction
- A signed statement from the contractor or owner confirming plan implementation
Common Exam Traps
- The CGP threshold of 1 acre disturbed is a federal permitting threshold; LEED applies the prerequisite to all projects regardless of acreage.
- This is a prerequisite, not a credit — worth 0 points but mandatory.
- Erosion controls address the cause; sediment controls address the symptom. The plan needs both.
- Local code, when stricter, replaces the EPA CGP — not the other way around.
A small infill project in Denver, Colorado disturbs 0.6 acres of land. The contractor argues that because the site is below the 1-acre threshold of the 2017 EPA Construction General Permit, no Erosion and Sedimentation Control plan is required for the LEED submittal. Is this correct?
Which combination of best management practices correctly pairs an erosion control with a sediment control on a LEED BD+C project ESC plan?