Balancing + fire + emergency storage → total reservoir volume per CPHEEO Chapter 12.
📘 Read the full CPHEEO Chapter →A service reservoir does three jobs at once: it balances the mismatch between constant WTP production and variable consumer demand (balancing storage), holds enough water for firefighting when demand spikes (fire storage), and provides a buffer against source or pump failure (emergency storage). Sizing one means summing all three components.
CPHEEO rule of thumb: total storage ≈ 33% of daily demand (roughly 8 hours). But for precise sizing — especially where fire demand is large or where emergency requirements are strict (hospitals, industrial consumers, pilgrimage centres) — the three components are computed separately.
Based on the CPHEEO Manual on Water Supply and Treatment, published by the Central Public Health and Environmental Engineering Organisation, Ministry of Housing and Urban Affairs, Government of India.
Size a service reservoir per CPHEEO Chapter 12 — balancing (25–35% of daily demand), fire (4-hour fire flow), and emergency storage (4–8 hr average).
Total storage is the minimum reservoir volume. Round up to a standard precast or cast-in-place size (0.5, 1, 2, 3, 5 ML etc.). Larger is generally safer but increases capital cost and water age (chlorine decay over retention time > 24 hours).
If total storage exceeds 50% of daily demand, your inputs are likely overly conservative — check the fire duration (do you really need 6 hours?) or emergency hours (is 8 needed?). Alternatively, split into multiple smaller reservoirs distributed across the zone for redundancy.