http://steamcommunity.com/sharedfiles/filedetails/?id=1300303792

thats it really, if its saying no sewage capacity then your sewage outlet might be blocked because it can't spread fast enough, try placing a second one

Thank you for the response. It looks like my "Sewega treatement" was running full. The number was not getting lower... I have used "irrigation sprinkler", because I had no water to connect "Sewage outlet". So the question is: the only way empty the "Sewage treatment" is to use "Sewage outlet"?

you always need at least 1 sewage outlet somewhere, it can be next to a river, ocean, or just on dry land or even just in a room that fills up, the sewage treatment building can eliminate 2500 litres of sewage a day but it still requires a sewage outlet to be connected just to work because the processed sewage needs somewhere to go and if the sewage treatment building reaches capacity then the excess sewage still needs somewhere to go

The irrigation sprinkler only uses fresh water from water towers.

Ok thank you, I will try it :)