100002238 - gradually releasing rainwater removal
Remove the following sentence:
“Where this is not possible or practical, retaining, treating, and then gradually releasing rainwater are acceptable.”
Homes-v4 SSc2: Rainwater management
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Credit language
© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Projects that must comply with local requirements of the National Pollutant Discharge Elimination System (NPDES) must follow Case 2.
Case 1. Low impact development
Use low-impact development (LID) techniques to minimize the amount of stormwater that leaves the site. Examples of acceptable techniques include the following:- planting areas with native or adapted plant material (e.g. trees shrubs);
- installing a vegetated roof;
- using permeable paving, consisting of porous above-ground materials (e.g., open pavers, engineered products), a base layer designed to drain water away from the home, and (often) a 6-inch-deep (150 millimeters) subbase; and
- installing permanent infiltration or collection features (e.g., vegetated swale, rain garden, rainwater cistern) that can handle 100% of the runoff from a two-year, 24-hour storm.
Table 1. Points for permeable area, as percentage of total lot area
| Percentage | Points |
|---|---|
| 50–64% | 1 |
| 65–79% | 2 |
| ≥80% | 3 |
Table 2. Conditioned floor area of reference home, by number of bedrooms
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 or more |
Floor area (square feet) |
1,000 |
1,600 |
2,200 |
2,800 |
3,400 |
4,000 |
4,600 |
+ 600 ft2 per additional bedroom |
Floor area (square meters) |
93 |
148 |
204 |
260 |
315 |
371 |
426 |
+ 55.6 square meters per additional bedrooms |
Table 3. Points for reducing total impermeable area
| Impermeable area (square feet) | Points |
|---|---|
| Reference home size * 1 | 1 |
| Reference home size * 0.66 | 2 |
| Reference home size * 0.33 | 3 |
Case 2. National Pollutant Discharge Elimination System (NPDES) projects
Using low-impact development and green infrastructure to replicate natural site hydrology, manage on-site the runoff from the developed site for the percentile regional or local rainfall events listed in Table 4. Use daily rainfall data and the methodology in the U.S. Environmental Protection Agency’s Technical Guidance on Implementing the Stormwater Runoff Requirements for Federal Projects, under Section 438 of the Energy Independence and Security Act, to determine the percentile amount.Table 4. Points for on-site management of water from rainfall events
| Percentile rainfall event | Points |
|---|---|
| 95th | 2 |
| 98th | 3 |
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Addenda
05/10/2018– Updated: 05/10/2018
Reference Guide Correction
Description of change:
Inquiry:
Ruling:
Campus Applicable
No
Internationally Applicable:
No
Credit language
© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Projects that must comply with local requirements of the National Pollutant Discharge Elimination System (NPDES) must follow Case 2.
Case 1. Low impact development
Use low-impact development (LID) techniques to minimize the amount of stormwater that leaves the site. Examples of acceptable techniques include the following:- planting areas with native or adapted plant material (e.g. trees shrubs);
- installing a vegetated roof;
- using permeable paving, consisting of porous above-ground materials (e.g., open pavers, engineered products), a base layer designed to drain water away from the home, and (often) a 6-inch-deep (150 millimeters) subbase; and
- installing permanent infiltration or collection features (e.g., vegetated swale, rain garden, rainwater cistern) that can handle 100% of the runoff from a two-year, 24-hour storm.
Table 1. Points for permeable area, as percentage of total lot area
| Percentage | Points |
|---|---|
| 50–64% | 1 |
| 65–79% | 2 |
| ≥80% | 3 |
Table 2. Conditioned floor area of reference home, by number of bedrooms
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 or more |
Floor area (square feet) |
1,000 |
1,600 |
2,200 |
2,800 |
3,400 |
4,000 |
4,600 |
+ 600 ft2 per additional bedroom |
Floor area (square meters) |
93 |
148 |
204 |
260 |
315 |
371 |
426 |
+ 55.6 square meters per additional bedrooms |
Table 3. Points for reducing total impermeable area
| Impermeable area (square feet) | Points |
|---|---|
| Reference home size * 1 | 1 |
| Reference home size * 0.66 | 2 |
| Reference home size * 0.33 | 3 |
Case 2. National Pollutant Discharge Elimination System (NPDES) projects
Using low-impact development and green infrastructure to replicate natural site hydrology, manage on-site the runoff from the developed site for the percentile regional or local rainfall events listed in Table 4. Use daily rainfall data and the methodology in the U.S. Environmental Protection Agency’s Technical Guidance on Implementing the Stormwater Runoff Requirements for Federal Projects, under Section 438 of the Energy Independence and Security Act, to determine the percentile amount.Table 4. Points for on-site management of water from rainfall events
| Percentile rainfall event | Points |
|---|---|
| 95th | 2 |
| 98th | 3 |
Addenda
05/10/2018– Updated: 05/10/2018
Reference Guide Correction
Description of change:
100002238 - gradually releasing rainwater removal
Remove the following sentence:
“Where this is not possible or practical, retaining, treating, and then gradually releasing rainwater are acceptable.”
Inquiry:
Ruling:
Campus Applicable
No
Internationally Applicable:
No