Water tank and sump sizing sheet
Water Tank and Sump Planner · build.nineclip.com/systems/water-tank-sump-size-family/
1. People and litres
People who live here (NBC: 5 if not known)
Litres per person per day (135 / 180)
Daily demand = people × litres, L
2. Supply
Supply comes: daily / alternate days / twice a week / tanker
Longest gap last summer, days
Tanker load, if any, L
3. Roof tank
Half a day = daily demand ÷ 2, L
Tank size to buy, L
Outlet at least 2 m above the top shower: yes / no
4. Sump
Daily demand × days to carry, L
Bigger than the roof tank and any tanker load: yes / no
Inside L × W × water depth to overflow, m
Stored litres = L × W × depth × 1,000
5. Before the walls go up
- Sump away from septic tank, soak pit, drains, low spots
- Overflow about 600 mm above ground, mosquito grating
- Overflow one size bigger than the inlet
- Overflow and scour over a grating, 50 mm air gap
- Outlet 50 to 75 mm above the floor, strainer fitted