Regulations
Boulder County SWPPP Checklist: Concrete Washout & Construction
Boulder County
Jurisdiction: Boulder County (Unincorporated Urbanized Areas & MS4 Boundaries)
Permit / authority: Governing permits: Boulder County Stormwater Quality Permit (SWQP) / CDPS General Permit
Boulder County enforces some of the strictest environmental and stormwater codes in Colorado. Requirements are dictated by the Keep It Clean Partnership and the Boulder County Storm Drainage Criteria Manual (SDCM). If you are pouring in Boulder County, your setup must meet these exact criteria.
1. The "100-Foot Watercourse" Trigger (Local SWQP Threshold)
The Rule: The state generally requires stormwater permits for projects disturbing one acre or more. The Boulder Nuance: Boulder County imposes a stricter local standard, requiring a Stormwater Quality Permit (SWQP) for construction activities that disturb less than one acre if they are within 100 horizontal feet of a watercourse. If you are conducting a small pour near a stream or wetland, you are fully subject to SWQP submittal requirements and control measure inspections.
2. Concrete Washout & Highly Alkaline Classification
The Rule: Control measures must be selected, designed, installed, and maintained to control all potential pollutants. Concrete truck washout is explicitly listed as a potential pollutant source that must be addressed. The Boulder Nuance: The county specifically highlights that "uncured concrete is highly alkaline" and classifies it alongside toxic pesticides and construction chemicals as a primary threat to stormwater. The SDCM criteria state that any control measures with loss of integrity, function, or breaches must be repaired immediately to prevent stormwater from transporting pollutants off-site.
3. SDCM & USDCM Design Standards
The Rule: Temporary and permanent stormwater quality controls (BMPs) are required to be designed according to approved engineering manuals. The Boulder Nuance: Boulder County requires that the design of temporary control measures be generally consistent with either the CDOT Erosion Control and Stormwater Quality Guide or the Urban Storm Drainage Criteria Manual (USDCM). Non-standard containment methods that do not meet these engineering specifications run the risk of failing the mandatory SWQP site plan review.
4. Compliance Re-inspection Fees & Penalties
The Rule: The owner and/or operator is responsible for managing construction activities to prevent the illegal discharge of sediments or other pollutants into the storm drainage system. The Boulder Nuance: Communities within the Keep It Clean Partnership can impose fines up to $1,000 per day for ordinance violations. Furthermore, if a site fails a county inspection due to non-compliance with SWQP requirements, Boulder County automatically invoices a Compliance Re-inspection Fee of $125 for every subsequent inspection required to verify compliance.
5. In-Channel Work Timing Recommendations
The Rule: Any work in or near a waterway requires a stormwater quality permit from the county. The Boulder Nuance: The Boulder County SDCM explicitly recommends that when possible, in-channel work should be performed between October 1 and March 31. This window historically provides a lower chance of high flood flows, excessive dewatering requirements, and control measure failures during construction.
