I bathe with my chiller water. that's so not true. But I do limit my waste water in these ways.
1. I make my own reverse osmosis water. Instead of sending the waste water down the drain, I send it to a gray water system that I use to water the lawn. Somebody told me me that the waste water will add salts to my lawn but I soak the s==t out of it every now and then. It is totally low tech. I drilled a hole in my wall and run the water to a rain barrel that either gravity feeds to my lawn or I pump it with my chiller pump to where I want to use it.
2. I chill my wort down to 100-115 through my plate chiller. I send the waste water to the same rain barrel and let it chill or I collect it and use it to clean because it is hot AF.
3. When my wort hits 100-115, I use my cooler pump, pre chiller chingadera and with 3 gallons of ice or 20 lbs of ice from dollar tree, I can chill it down to 65 in less than 10 minutes.
4. when I mix my star san, I use RO so I can save it and I use it to soak my water bottles, cutting boards, coffee pot, etc.
Good luck. Find what works for you.