Construction General Permit for Stormwater Runoff

Renewal Process Begins Soon and There is Cause for Concern

In the next few months, the California State Water Resources Control Board (SWRCB) will release the long-awaited DRAFT version of the Construction General Permit (CGP) for stormwater runoff from job sites. The CGP was last renewed by the SWRCB in 2010 and went into full effect in 2012. For builders and contractors, the CGP is required on nearly all job sites in California greater than one acre in size and depending on site conditions can be a major cost item.   

The CGP requires construction phase job site planning for wet weather conditions and also requires actions before, during and after rain events in an effort to prevent soil erosion. Common requirements for permit holders include preparing a stormwater pollution prevention plan (SWPPP), installing erosion and sediment control best management practices (known as BMPs) that prevent and reduce soil erosion and loss, and having trained staff perform job site inspections on BMPs before and after rain events.  

The CGP, adopted in 2010, introduced a new soil loss risk-based approach for determining and guiding the level of BMP effort that must be expended at the job site, and new requirements for job site personnel responsible for inspecting BMPs and sampling and monitoring of stormwater runoff. The building industry adapted to these new requirements, while finding ways to streamline and economize effort and time expended on compliance.  

The Construction Industry Coalition on Water Quality (CICWQ) and our member associations have been working for many years to understand how the permit conditions are affecting the construction and building process: what works, what doesn’t, and what needs to be changed. Paramount to the construction industry is preventing any type of numeric effluent limit (NEL) for sediment or other pollutants such as metals discharged from construction job sites. 

In working with SWRCB staff and discussing potential new permit conditions, the State is considering imposing NELs in certain watersheds and waterbodies in California where theirwater quality standards — known as Total Maximum Daily Loads (TMDL) — are in place for metals from construction sites. The construction industry is adamantly opposed to NELs for many different technical and legal reasons. In this instance, there are essentially no technologies available that can treat various metals found in construction site runoff to the levels necessary to achieve the TMDL NELs. If treatment were required to meet a NEL, the cost impact to the construction sector, including housing, is significantly greater than current practices (see CGP Stormwater Permit Cost Impact Table).  

When the CGP was last renewed in 2010, CICWQ worked with our member companies and associations across the state and the Building Industry Legal Defense Foundation to successfully prevent the SWRCB from adopting numeric limits. We must do the same in 2020, as exceeding a NEL can lead to a permit violation, and then significant legal fees, fines and penalties.  

For more information, please contact:

Mark Grey, Ph.D., Technical Director, Construction Industry Coalition on Water Quality:mgrey@biasc.org 

Robert Patterson, CPESC, ToR, QSP/QSD, Director of Environmental & Safety Compliance, Baldwin & Sons: rpatterson@baldwinsons.com

Cost Impact Comparison—Homebuilding Example

Existing Permit versus Proposed Requirement to meet NEL