This credit is a combination of stormwater quality control and quantity control. There’s even a pathway for zero-lot-line urban projects.

Executing this credit may be expensive, but it can also be economical; it varies greatly depending on site, soil, and project. Additionally, teams should take some time to better understand the historical conditions of the site; this is important as you’ll need to use low-impact development (LID) and green infrastructure (GI) strategies that mimic the site’s natural pre-development hydrology.

There’s a catch, though. This credit may be difficult to achieve even with LID and green infrastructure strategies in place. You will need to ensure that your strategies actually keep rainwater on the site. For example, a green roof or a rain garden that drains to a municipal storm sewer—which is common—won’t cut it! Many projects, especially urban ones that don’t have large vegetated site areas to work with, are likely to find this one out of reach unless rainwater is captured and reused on the site.

SITES-LEED equivalency

SITES-LEED equivalency is not offered for this credit. The related SITES credit cannot be used to automatically earn this LEED v4.1 credit.

What’s New in LEED v4.1

• Two options previously available in v4 have been removed (Option 2 Natural Land Cover Conditions and Option 3 Permeable Lot Area).
• The term “manage” in v4, which many teams find confusing, is replaced with “retain (i.e. infiltrate, evapotranspirate, or collect and reuse).”
• The thresholds for retaining rainwater have been reduced, where the lowest threshold is now the 80th percentile rainfall event as opposed to the 95th event, and the highest is now the 90th instead of the 98th.
• The thresholds for zero-lot-line projects also decreased.
• Zero-lot-line projects that meet the credit’s minimum percentile threshold but can’t retain additional rainfall onsite have the option to retain additional rainfall offsite, as long as the LID/GI system is designed to accommodate rainwater from the project.
• Acceptable low-impact development (LID) techniques have been clarified.
• SITES-LEED equivalency is no longer offered for this credit.

Should I Upgrade?

Yes! The rainfall retention thresholds have been reduced, making the credit much more achievable by all projects.