We travel in a lot of areas that perpetually have boil water warnings. In the beginning we were concerned about these warnings. We were never concerned about city water we added to our tank, no more than we're concerned with growth in our home water lines. Be sure stuff grows in your water lines at home as well.
If your're a water worrier like we were when we started you can add a cold water filter for drinking and cooking. We had one in the motorhome from General Ecology capable of 700 gallons that would last us 7 months. These filters remove practically everything including viruses. They are low flow, about a 0.5 gallons per minute.
Our's was similar to 770310 in the following link.
The following link refers to the capability of the unit. We connected it to a bar type faucet.
Water going to this filter was pre-filtered by a traditional RV filter to remove the larger items and save the more expensive filter. (The typical Walmart's RV filter is 100 microns, 250 time less capable than this General Ecology filter).
Water Microfiltration System General Ecology Versa Pure Filter Stainless New | eBay
As we've become more experienced we've become less concerned with the boil water orders, finding the locals ignore them totally.