I think most people don't realize municipal water is run through a sand filter and chlorinated after. Coca cola runs municipal water through sand filters for their drinks.Obviously you would need multiple filters. And a plan for a pre-filter. And a method of making a long-term filter.
If your plan would be just a single life straw, or small sawyer filter, you would probably be good for only about 1 to 2 weeks if only one person, before it feels like sucking water out of a piece of wet firewood.
I’ve drank a lot of iodine tablets, and out of a lot of filters, from a lot of weird places. Filters are great. But you will need multiples. And the little ones will clog fairly quickly.
You would probably need at least a few midsize units. And should be able to rig a filter system. Maybe through something like a 4 inch PVC pipe. A few feet long. Sand layers on top, charcoal layers on bottom. Gravity feed. Replace materials occasionally.