Storm Water Control
Site retains, infiltrates, or treats stormwater on-site — rain gardens, permeable surfaces, cisterns.
Description
The Storm Water Control badge recognizes projects that retain, infiltrate, or treat stormwater on-site rather than discharging it to the municipal storm sewer. The badge sits within the Moisture pillar because effective stormwater control protects the home's foundation and the surrounding site equally — the same rain that erodes a slope is the rain that ends up in a basement.
Earning the badge requires moving meaningfully beyond the Moisture-pillar baseline of gutters and grading: green infrastructure (rain gardens, bioswales, dry wells), permeable surfaces, and/or cisterns sized to capture the design storm. The result is an improved water balance — more infiltration into the local water table, less peak flow into the storm sewer, less downstream flood risk.
Required standard requirements
To earn this badge, the project must meet all of the following existing GreenStar requirements:
Additional badge criteria
Beyond the required standard requirements above, the project must also satisfy:
Design storm capture
- 01.
Site is designed to retain or infiltrate the first 1 inch of rainfall on impervious surfaces — captured volume calculated as: (impervious area in sq ft × 1 inch ÷ 12) ÷ 7.48 = required storage in gallons.
- 02.
OR the project meets the local stormwater management ordinance's "green infrastructure first" or "low impact development" pathway, whichever is more stringent.
- 03.
Existing-home renovation pathway: at least 50% reduction in net stormwater discharge from the site, measured pre/post by impervious-area change or modeled in a tool such as EPA's National Stormwater Calculator.
Acceptable practices
- 01.
Bioretention / rain gardens sized at ~5–10% of contributing impervious area, with native plants suited to alternating wet/dry conditions.
- 02.
Permeable paving (pavers, porous concrete, porous asphalt) on driveways, patios, and walkways — counted as pervious in the design-storm calculation.
- 03.
Rainwater cisterns (above- or below-grade) sized for the design storm and either irrigation-discharged or used for non-potable indoor uses (toilet flushing, laundry — local code dependent).
- 04.
Dry wells or infiltration trenches for downspout discharge, sized using local infiltration rate (perc test required where soils are clay-heavy).
- 05.
Vegetated swales, dry creek beds, and stepped check-dams where slope and area permit.
- 06.
Green roofs or roof gardens — counted as impervious area reduction equal to the modeled retention coefficient (typically 0.4–0.7).
Site-specific requirements
- 01.
No discharge of captured stormwater within 10 ft of the foundation or onto adjacent properties.
- 02.
Sediment forebay or pre-treatment required for cisterns and infiltration features receiving runoff from parking or driveway surfaces.
- 03.
Where greywater or rainwater is reused indoors, system must meet the same plumbing-code requirements as for the Zero Water Capable badge.
Documentation
- 01.
Stormwater management plan showing impervious areas, drainage paths, design-storm calculation, and each retention/infiltration feature with sizing.
- 02.
EPA National Stormwater Calculator output (or equivalent local model) showing pre- and post-development runoff volumes.
- 03.
Soil infiltration / percolation test results for sites relying on dry wells or infiltration trenches.
- 04.
As-built photos of installed features at completion.
Verification by tier
Evidence the project team submits at each certification tier. Cumulative — higher tiers include everything below unless noted otherwise.
-
Certified
Self-attestation- 01.
Stormwater management plan showing impervious areas, drainage paths, design-storm calculation, and each retention/infiltration feature with sizing.
- 01.
-
Silver
Documents + photos- 01.
EPA National Stormwater Calculator output (or equivalent local model) showing pre- and post-development runoff volumes.
- 02.
Plant list for any bioretention areas; cut sheets for permeable paving or cisterns.
- 01.
-
Gold
Third-party test- 01.
Soil infiltration / percolation test results for sites relying on dry wells or infiltration trenches.
- 02.
On-site verification by a civil engineer or landscape architect at substantial completion + as-built photos of every installed feature.
- 01.
-
Platinum
Post-occupancy verification- 01.
Post-completion observation log demonstrating the system functioned through at least one design-storm event (or photo + rainfall record after a qualifying storm) within the first 24 months.
- 01.