Are sump pumps allowed in North Seattle? If so is there any particular code to which can limit installing one for sewage purposes (such as toilet,shower,sink)
Sewage Ejectors are legal to use in Seattle.
I like the Zoeller brand with a 30" basin.
It comes with a 4/10 hp motor.
2" discharge and 2" vent.
The 2" vent needs to vent through the roof.
You can't use an AAV on a pump system.
This model is a Zoeller 912-0010
In Seattle, they like to see it drained into a 4" waste line.
This pump would handle several bathrooms.