Cost calculations are performed in WaterCAD in Darwin Designer based on the formula:

Cost = Unit Cost x Length

for each pipe element, where the unit cost is a function of the pipe diameter. The total costs are the sum of the costs for each element.

The user specifies the cost functions and has the option of having different cost functions for different locations (e.g. new developments, central city, stream crossing). The user must identify which pipes are to be included in the estimate and which pipes are assigned to each cost function.

An overview of the steps consists of:

The detailed steps are listed below.