How to generate a sewer

A sewer can be generated for a water calculation when using the configuration wizard.

Editor → Current Situation (Ribbon tab) → Overlays (Ribbon bar) → The Water Overlay (Left panel) → Configuration Wizard (Right panel)

How to generate a sewer for a Water Overlay:

Open the configuration wizard of the Water Overlay.
Continue to the step concerning sewer areas
Select the 'generate' option.
Set the maximum urbanization factor. Every neighborhood with a lower or equal urbanization factor will get a sewer area. If you want sewer areas in every neighborhood, set this value as high as possible.
Set the desired amount of storage for the sewer areas.
Set the desired pump capacity for the sewer areas. Note that in contrast to the resulting attribute, the unit here is in mm/hour.
If you have your own dataset for Sewer Overflows, or if you don't want water to flow back from the sewer onto the surface water, deactivate the option for generating Sewer Overflows.
Select 'Next' to start the generation process.
Close the configuration wizard.

Notes

Sewers are composed of sewer areas, and constructions with a SEWERED attribute. So even though an entire neighborhood may be covered by a sewer area, the sewer is only considered "present" under the constructions which are connected to the sewer.
When a neighborhood does not have an URBANIZATION attribute, the value is considered to be 0, which is lower than any selectable urbanization factor in the sewer generation step. This means the neighborhood is always given a sewer area when generating.
When generating sewers, different amounts of sewer storage can be applied to sewers in pre-1965 neighborhoods and post-1965 neighborhoods. A neighborhood is considered post-1965 if any construction has a CONSTRUCTION_FINISH_DATE which resolves to after 1965.
When automatically generating sewer overflows, the generated sewer overflow will be placed on the intersection of the sewer area, an overlapping water area, and a water terrain. If no water area or no water terrain intersects with the sewer area, no sewer overflow is generated.