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.