Question 1: Does your project site include stormwater management strategies such as downspout disconnection, rainwater harvesting, rain gardens, bioretention, bioswales, pervious hardscapes, or a green roof?

If yes, proceed to question 2. If no, you won’t be able to achieve this credit unless you undertake site renovations.

Question 2: Do your stormwater management strategies combine to receive stormwater flow from at least 25% of the impermeable site area?

If yes, you have a reasonable chance to meet the credit. If no, it’s probably not going to happen.

If you’ve made it this far, your next challenge is to complete the required credit calculations. We’ve addressed these in the FAQs below.

What’s New in LEED v4

• LEED now requires projects to use onsite low impact development (LID) and green infrastructure (GI) rainwater management techniques.
• USGBC added a metric for testing compliance that calculates the total volume of runoff for the 95th percentile of regional or local rainfall events, instead of one and two-year storm events.

Readiness Review Questions

• Is the ratio of pervious to impervious surfaces likely to bring the project to compliance through natural infiltration strategies? 


• Do rainwater collection systems such as cisterns, detention ponds, and bioswales already exist onsite? If so, are there design or construction documents demonstrating their capacity? If not, is it feasible to introduce rainwater collection to the site? What are the likely costs and efforts associated with this? 


• What opportunities are there for installing additional vegetation or otherwise increasing pervious areas?

• What opportunities exist for installing or expanding other low-impact development features onsite?