eli5 Is there a reason the waste water like from showers can’t be filtered through pipes and used for toilet water?

Question

eli5 Is there a reason the waste water like from showers can’t be filtered through pipes and used for toilet water?

In: 797

Answer 1

To use gray water, you have to install a complete system of tubes, pump and filters. And maintaining it .. then you have to make sure gray water system and drink water system can never connect…..
So basically it’s to expensive