How it works
Multiply the mob size by the average daily water consumption per head for the relevant class of stock. The per-head figures reflect average needs under moderate Australian conditions (15–25°C, mixed pasture and dry feed). In summer heat or when grazing dry feed, requirements increase significantly. Storage should cover at least 2–3 days as a buffer against pump or bore failure.
Worked example
200 adult cattle × 70 L/head/day = 14,000 L/day. For a 3-day storage buffer: 14,000 × 3 = 42,000 L (42 kL). A pair of 25,000 L poly tanks provides adequate buffer with redundancy.
Assumptions & limitations
Per-head daily water requirements used: adult cattle 70 L, weaner cattle 35 L, adult sheep 8 L, lambs 3 L, adult goats 10 L, horses 55 L. These are temperate-condition averages. In extreme heat (>35°C) or when stock are on dry, dusty feed, increase the estimate by 50–100%. Lactating cows need up to 30% more than the adult average. Source: MLA Beef — Water Quality and Quantity.