In most situations you cant have too much potable water.
10 normall size water bottles is probably more than is sensible to carry at one time though.
In hot or arid conditions it would be prudent to carry some gallons of drinking water in a vehicle, but this might be better in several larger containers rather than numerous regular size water bottles.

As regards owning 10 or more water bottles rather than carrying that many at once, 10 is rather a lot to keep in a row on the shelf.
10 is not that many if you have 2 at work, 2 in each of 2 vehicles, 2 in a bug out kit, and 2 in daily use.

In hurricane country ten 5-gallon bottles is just getting started.

The bottles need to be cleaned and washed periodically. We used to keep the empty bottles in the attic and wash them out at the start of each hurricane season. It's a pain but we used them often enough to stay motivated (hearing that the city sewer plant was five feet underwater discourages tap water use for a while).

I don't remember how many bottles we had.

Agreed. Our "bottles" consist of 30-gallon food quality plastic drums.

I've been edc'ing one in my car...nice to have