What size rainwater tank do I need for my garden?
Start with these easy rules of thumb, then fine-tune using your local rainfall and roof catchment:
- Courtyard pots and herbs – a slimline tank around 1,000 L keeps small planters thriving.
- Compact veggie patch (up to 50 m²) – step up to a 2,000–3,000 L round or slimline tank for reliable irrigation.
- Family lawn and mixed beds (100 m² or more) – look at a 5,000 L (or larger) round tank to cover regular watering.
For a precise figure, multiply your available roof area (in m²) by your postcode’s average annual rainfall (in mm), then divide by how many times you expect to empty and refill the tank each year. Need help crunching the numbers? Use Polymaster’s online water tank calculator – or call our team – and we’ll size the perfect rainwater tank for your garden and climate.