Water Demand Estimator
Estimate your household's daily and annual water needs across drinking, cooking, washing, toilet, garden and livestock.
Your household
Vegetable garden / growing beds.
Your water needs
Daily total
— L/day
- Weekly
- — L
- Annually
- — kL
How this calculator works
Water demand is the number that sizes your tank, your catchment and your whole water plan — and most people underestimate it by half. This tool estimates demand from the same per-activity figures used by water-supply engineers:
| Activity | Typical use |
|---|---|
| Drinking & cooking | 2.5–7.5 L per person/day |
| Personal washing | 8 L (bucket) to 120 L (long shower) |
| Toilet | 0 L (composting) to 25 L (full flush) |
| Laundry | 5–30 L per person/day |
| Garden | ~5 L per m² per day in the growing season |
| Livestock | 0.5 L (chicken) to 60+ L (cattle) per animal/day |
Benchmarks for sanity-checking
- Survival minimum (WHO): ~15–20 L/person/day for drinking, cooking and basic hygiene.
- Frugal off-grid: ~40–60 L/person/day.
- Comfortable off-grid: ~100–150 L/person/day.
- Conventional suburban home: ~200–300 L/person/day.
These are planning figures. Measure your own use with a tank gauge or meter — reality is the only number that matters when you're sizing storage.