@kate2025 I've thought about this today. It's pretty confusing at first and it's impossible and frustrating trying to make life sterile. Do the things with biggest return that are recommended by the scientist who do the work .
I also like the philosophy of our mentor, Sue, who says she wants to live and enjoy life and not let the disease define her.

I've ended up trying to make my life simpler and doing the things with biggest impact first.
I had hot water heater turned up to 135 right away. That reduces concern about warm tap. (Falkenham) I'm in city and he said most municipalities don't have it in cold water, though I mostly drink boiled.
I plan to ask plumber about filters next time he's out-again to make it simpler.
I took the head off my shower, but a rainfall shower head works, too (per Falkenham).
I boiled things for a while, but got the Bololo, which again makes life simple and frees time.

Hang in there. You'll figure out a routine-and will probably keep tweaking it like the rest of us. : )