Welcome Dennis!

Glad to have you join us, there are many folks that participate (& Lurk) on these forums and quite a few of them are knowledgable about the many different aspects of being prepared.

Water storage concerns:
Consideration needs to be given to things like what if...the water containers leak or get hit / bumped into / knocked over or off of a shelf? There will be others that depend upon individual situations.

While 1 gallon milk jugs are great for storage, they need to be monitored for plastic degradation due to water chemicals, sunlight and ultraviolet exposure, heat, freezing, and not to forget...being close to other chemical containers as flavors and smells can leach through plastic containers.

The floor loading issue is much different if you are on a single floor building with a concrete floor versus a wooden floor over a basement or in a multi floor structure.

As others have noted, there is "hidden water storage" in most houses that have hot water heaters, commodes with storage tanks in back or on top of them, plus a certain amount that will reside in the house piping itself. In the event that you have warning of an incoming issue/disaster as we do in Florida with hurricanes, it is wise to fill tubs, and other containers with water well before the storm is close. Having water purificaton available is always a good thing especially for those events where you simply do not have water storage available and need to "do it on the fly".

So draw up a log to sit on, hang around the campfire with us and feel free to chime in.

Regards,
Comanche7