A lot of things are undervalued in this world, let me give you an analogy that covers an alternate use of water. What you think is open to debate.
When you run a clothes washing machine, about 50 litres of grey water spurts out the back and is sent down to the sewer line. To me the used grey water from the clothes washing machine is very useful so it would be collected into a water butt tank. The grey water is quite hot so the water butt tank gives off heat during wash cycles. The grey water also contains detergent chemicals that break up organic compounds and perfumes. The water butt feeds into a toilet cistern tank, you flush 5 litres of grey water at a time. The cleaning chemicals that are still in the grey water act on the sewer pipe and help break up skid marks deep in the pipe. Why flush with fresh water when you won't drink it? I wouldn't care much if the water I flushed with had a grey hue to it; I'm guessing the toilet bowl would need to be grey in colour to hide the grey stains from the flushes.
My analogy doesn't stop there. When you defecate and urinate, the materials you expel are the harder portion of your food and chemicals that can't be broken down by your body, they are quite tough. I thought to myself that sewage contains tough materials that are embedded in fats and oily fibre compounds. They could be sent to a tank beyond your home, the tank has air pumped out of it, that causes the water content of the sewage to boil away without heat being applied. The dry material left in the tank is sent to an incinerator to be burnt. The ashes of the burnt sewage could be mixed with resins or plastics to make bricks and road surface material.
Because your poop contains some very tough particles, those particles could become ingredients to make roads and bricks. The incinerator would burn away the soft fatty portion of the dry sewage leaving behind dusty ashes that are very strong when mixed with resins or cement.
This is a common thought I have in my head. I always thought it was daft to use fresh drinking water to flush a toilet.
