Refer to the stormwater management plan or consult with your building’s civil engineer to learn the site’s imperviousness. If it is less than 50% impervious, the stormwater management plan must equalize the pre- and post-development peak discharge rates a

Refer to the stormwater management plan or consult with your building’s civil engineer to learn the site’s imperviousness. If it is less than 50% impervious, the stormwater management plan must equalize the pre- and post-development peak discharge rates and quantities from the one-year, 24-hour, design storm. If your site has more than 50% impervious cover, the plan must reduce the volume of stormwater runoff by 25% from the 1½-year, 24-hour, design storm.