The first step is creating unit cost functions to be used in the cost estimating.

Click the Cost/Properties tab from the right pane and click the New button in the right pane to create a new cost function. It is advisable to give each function a more useful name than the default "New Pipe-1". For example use "congested urban area", "new subdivision," "state highway", or "open field" as cost function names.

There must be a unit cost for each diameter that is included in the cost calculation. No interpolation is done. For example, if a 10 in. (250 mm) pipe is included in the scenario for which costs are calculated but a unit price for a 10 in. pipe is not included in the cost function, the cost calculation will fail and an error "Unable to match at least one scenario derived pipe diameter to the specified cost table" will appear under user notifications. To correct this, add the unit cost for that diameter.