- 1 mm rainfall
- 1 litre per 1 m² before losses.
- Runoff coefficient
- The fraction of rainfall that runs off the surface rather than remaining or evaporating.
- System efficiency
- Additional losses in filters, first flush and conveyance.
- Demand coverage
- The share of demand met by harvested rainwater.
Rainwater planning
Rainwater glossary
Definitions of rainfall millimetres, runoff coefficient, efficiency, storage, first flush, overflow and reliability.