Can you get the water out of the well when the power is out? Most well pumps take 220V electricity, most generators can run one no problem. Hand pumps will lift 30’ or so.
Not difficult to setup if done in advance. Plus drilling your own well (for emergency use, of course) is not that big a deal. Plans are on the net to drill your own well using garden hoses and PVC pipe. Won’t work everywhere,m but worth researching.
Creek water can be made potable, but must be set up in advance, and treatment methods verified. Water borne disease is not good when in survival mode.
How will the creek water get to the house? You will get 1 or 2 flushes from a 5 gal bucket. It gets old fast toting those uphill.
What's that saying? If it's yellow let it mellow; if it's brown flush it down.
Do city sewer systems continue to function if power is out for extended periods of time? What with sewage treatment and all, would the sewers get clogged and back up? Fortunately I'm on a hill, so folks on the flatlands might be concerned more than me.
The newer toilets only use 1 or 2 gallons of water and a couple of plastic jugs will flush one a day.
Years ago there was a magazine, probably still being published, that showed people how to do everything they needed to survive on the land. My mother was a ‘back to the land’ person and lived it, with 3 yrs of food supply ahead all the time. And she owned a real estate business for years in a very rural area...mostly farms and land.
So I have the expertise needed to survive. I always helped her can and preserve food. My grandparents and great grandparents made it through the Great Depression via self sustained farms.
I am concerned with the UN wanting to take over all water supplies in USA, that seems the wrong approach with wells and rivers at stake.
Those activities will become part of your life and you won't have a lot of the normal distractions if the SHTF.