First you need to be clear ...

First you need to be clear what you mean by demand. If this is the distribution input needed to maintain supplies to all connections from the water distribution system, and at the same time keep the system adequately pressurised, then in addition to the actual consumption by users drawing water from the connections you will need to consider losses from the network. These physical losses can be large, especially if there has been a lack of active leakage control in the past. Nowadays we talk about NRW (Non-Revenue Water), which includes not only the physical losses but also commercial losses (e.g. water theft and unbilled consumption due to poor connection and metering records). I would not be surprised if NRW in Libya was 50% or more of distribution input, but it can be difficult to estimate.