The County requires stormwater pollution controls during construction and as part of the post-construction conditions. Pollution prevention must be part of the construction phase of all projects through implementation of effective erosion, sediment and pollution controls at all times. Pollution prevention is integrated into the final project designs through site design measures and stormwater facilities designed to infiltrate and treat runoff from post-construction impervious surfaces. Visit the Marin County Stormwater Pollution Prevention Program page to learn more about new and redevelopment requirements for your project.