That article is relatively sensible, and it also mentions why the writer advocates storing some water, or at least getting a filter, even though they suspect water service will continue to operate.

Here's one hypothetical scenario that might be intuitive, not from the article... Say, you live in a dense part of the city, and there's suddenly a lot of confirmed cases around you, so your family decides to stay home for a week, to wait&see how this plays out and what government help arrives. All your city utilities work, but much of the city water utility workers can't afford to live in the city, or otherwise have to stay home, and the remaining workers can't keep up with the ordinary day-to-day level of repairs and maintenance. A pipe fractures, brown water comes out your faucet, and now you have to decide whether to venture out to try to find a store open that has bottled water, and possibly bring the virus back to your family, or stay in and hope water will be fixed and known-safe within 3 days. Ordinary bottle water is $1-$2 a gallon, off-the-shelf from the local store, and some insurance and peace of mind against a very bad and not-too-unlikely situation.