Answer two quick questions and we'll recommend the smallest tank that covers your household or harvesting need — no oversizing, no guesswork.
Rough guides if you'd rather not run the numbers.
A 2,500L vertical tank usually covers 5 days of backup at average use.
Most families land on 2,500L–5,000L depending on backup days wanted.
A typical George-area roof (100–150m²) can fill a 5,000L tank in a good rain month.