Calculate your quantity
Use your measured area and the actual product specification. The result updates as you change an input.
How this estimate works
Potential gallons = connected roof area × rainfall inches × 0.623 × collection efficiency.
The arithmetic describes a planning volume or sketch. Local climate, plant needs, pressure, flow, rainfall, and equipment ratings determine actual irrigation design.
Before you order
- Check local weather and plant water needs.
- Confirm equipment pressure, flow, and manufacturer coverage.
- Check local water rules and the site drainage path.
Planning estimates can differ from delivered or installed quantities.
Reference
US EPA WaterSense: Water Budget Tool. Product specific rates and installation specifications take precedence over general defaults.