Apparent (Commercial) losses are losses that are not due to physical leaks in the water network, but are caused by other factors. Apparent losses can be grouped into the following categories based on their origin:

• meter inaccuracies due to damage or incorrect customer and (or) bulk water meters
• data handling and accounting errors and bad billing systems
• unauthorized consumption due illegal connections.

Summarising the above, apparent losses comprise all water that is successfully delivered to the customer but which is not metered or recorded accurately and thus causes an error in the amount of customer consumption. In water supply networks without legal instruments and with numerous illegal connections, apparent losses may represent significant amounts of water. Apparent losses are creating production costs without enerating revenue for the utility. Thus, apparent losses must be valued at the retail cost of waterand are therefore in many cases the most expensive losses that a water utility will encounter.

Reducing apparent water losses can be achieved in many cases at relatively low costs and is therefore usually a good starting point which pays off quickly to the water utility