flood Intermediate Featured
EPA Stormwater Calculator
Estimate stormwater runoff reduction from green infrastructure practices
Addresses
Flooding
- Cost
- Free to use
- Proprietary-Free
- Difficulty
- Intermediate
- Language
- —
- Updated
- 2024
You provide
- Site location
- Soil type
- Land cover / surface
- Local rainfall record
- Proposed LID controls
You get
- Annual runoff volume
- Runoff reduction from LID
- Rainfall-retention performance
- Climate-scenario comparisons
Overview
The EPA National Stormwater Calculator estimates the annual amount of rainwater and frequency of runoff from a specific site, and shows how low-impact development (LID) controls can reduce it. It draws on national soil, topography, and rainfall datasets.
Key features
- Site-specific runoff calculations from national datasets
- Modelling of green-infrastructure / LID controls (rain gardens, permeable pavement, cisterns)
- Flood-risk and water-quality improvement analysis
- Built-in climate-change scenario comparisons
Who it’s for
Site designers, municipal stormwater staff, and developers evaluating green-infrastructure options.
Getting started
Use the web version or download the desktop app, enter a location, and add LID controls to compare scenarios.