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LEED v2009
Neighborhood Development
Green infrastructure & buildings
Rainwater management

LEED CREDIT

ND-v2009 GIBc8: Stormwater management 1-4 points

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Credit language

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© Copyright U.S. Green Building Council, Inc. All rights reserved.

Requirements

Implement a comprehensive stormwater management plan for the project that retains on-site, through infiltration, evapotranspiration, and/or reuse, the rainfall volumes listed in Table 1. Rainfall volume is based on the project’s development footprint, any other areas that have been graded so as to be effectively impervious, and any pollution-generating pervious surfaces, such as landscaping, that will receive treatments of fertilizers or pesticides. The percentile rainfall event (Table 1) is the total rainfall on a given day in the record that is greater than or equal to X percent of all rainfall events over a 20- to 40+-year period. For example, a 95th percentile event in a particular region might be 1.5 inches (40 millimeters), which would then be the volume to retain. To determine the volume to be retained, projects may use NOAA’s published national rainfall data, run an approved stormwater model, or independently gather local rain gauge data and rank rainfall events. One hundred percent of the water volume from rainfall events up to the X percentile event must not be discharged to surface waters unless the harvested and reused runoff is authorized for discharge or allowed to be discharged into sanitary treatment systems.

Table 1. Points for retaining stormwater on-site

Percentile rainfall event (determines total volume from development footprint to be retained)

Points

80th

1

85th

2

90th

3

95th

4

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Addenda

2/2/2011Updated: 2/14/2015
Rating System Correction
Description of change:
Replace the paragraph (continues onto next page) with the following:Select BMPs from the Washington State Department of Ecology\'s Stormwater management Manual for Western Washington, Volume V, Runoff Treatment (2005 edition), or locally approved equivalent, whichever is more stringent. If the BMPs are comparable in stringency, choose BMPs that are most appropriate to the project site and region. BMPs must also comply with all federal, state, and local regulations.
Campus Applicable
No
Internationally Applicable:
No
11/3/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the sentence under Table 1 that begins with "Projects that earn," replace "each" with "one"
Campus Applicable
No
Internationally Applicable:
No
2/2/2011Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the paragraph (continues onto next page) with the following:Select BMPs from the Washington State Department of Ecology\'s Stormwater management Manual for Western Washington, Volume V, Runoff Treatment (2005 edition), or locally approved equivalent, whichever is more stringent. If the BMPs are comparable in stringency, choose BMPs that are most appropriate to the project site and region. BMPs must also comply with all federal, state, and local regulations.
Campus Applicable
No
Internationally Applicable:
No
11/3/2010Updated: 2/14/2015
Rating System Correction
Description of change:
In the sentence under Table 1 that begins with "Projects that earn," replace "each" with "one"
Campus Applicable
No
Internationally Applicable:
No
11/3/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace table
Campus Applicable
No
Internationally Applicable:
No
2/2/2011Updated: 2/14/2015
Reference Guide Correction
Description of change:
Below the Washington State Department of Ecology entry, add the following text:Note that only BMPs related to infiltration, reuse, and evapotranspiration are appropriate to meet the credit requirements, though other types of BMPs are also found in the manual, for example: BMP T11.11 Coalescing Plate (CP) Separator Bay, BMP T6.10 Presettling Basin, and BMP T8.10 Sand Filter Vault.
Campus Applicable
No
Internationally Applicable:
No
11/3/2010Updated: 2/14/2015
Rating System Correction
Description of change:
Replace table
Campus Applicable
No
Internationally Applicable:
No
1/1/2013
LEED Interpretation
Inquiry:

Can the surface area of existing streets be exempted from the impervious surface area used to calculate the stormwater volume to manage?

Ruling:

For the purposes of GIBc8, project teams are allowed to exempt the surface area of existing street infrastructure that is a part of the public right of way (\'street\' as defined in the LEED-ND glossary) from the impervious surface area used to calculate stormwater volume to manage. Applicable Internationally.

Campus Applicable
No
Internationally Applicable:
Yes
See all forum discussions about this credit »

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USGBC logo

© Copyright U.S. Green Building Council, Inc. All rights reserved.

Requirements

Implement a comprehensive stormwater management plan for the project that retains on-site, through infiltration, evapotranspiration, and/or reuse, the rainfall volumes listed in Table 1. Rainfall volume is based on the project’s development footprint, any other areas that have been graded so as to be effectively impervious, and any pollution-generating pervious surfaces, such as landscaping, that will receive treatments of fertilizers or pesticides. The percentile rainfall event (Table 1) is the total rainfall on a given day in the record that is greater than or equal to X percent of all rainfall events over a 20- to 40+-year period. For example, a 95th percentile event in a particular region might be 1.5 inches (40 millimeters), which would then be the volume to retain. To determine the volume to be retained, projects may use NOAA’s published national rainfall data, run an approved stormwater model, or independently gather local rain gauge data and rank rainfall events. One hundred percent of the water volume from rainfall events up to the X percentile event must not be discharged to surface waters unless the harvested and reused runoff is authorized for discharge or allowed to be discharged into sanitary treatment systems.

Table 1. Points for retaining stormwater on-site

Percentile rainfall event (determines total volume from development footprint to be retained)

Points

80th

1

85th

2

90th

3

95th

4

See all LEEDuser forum discussions about this credit » Unsubscribe from discussions about ND-v2009 GIBc8