What are you prepping for?

I'm gonna state right up front that I am not wanting to discourage any one from being a prepper. Stocking up, no matter the reason, is a wise policy. You could lose your job, or get hurt tomorrow. Having a stock of food would tide you through.
Some folks aren't prepping at all. There are several reasons for that.
1. They expect the government to take care of them.
2. They are Christians who believe in a rapture.
3. They don't believe the country could face such a crisis.
4. They are just plain lazy.
Some people talk about prepping for a sixty or ninety day event. Where do you get that number from? Calimities recorded in history have stretched far longer, and the promise of GOD is seven years. What good will three months supply do you?
What you see as an approaching rain might be the storm of the century so to speak, I don't know, but it is better to be prepared and be wrong than to be unprepared.
For today, think about your water. What are your plans, how much will be enough? How will you store it? How will you protect it?
First off what are your basic needs? One person will consume roughly one gallon of water per day. Bathing cleaning and such adds much more. In normal life you would use 30-40 gallons every day conservatively. We are not talking normal life though. Best to plan on getting and staying dirty. Bathing will be a luxury. So if it is you and the wife, will 5,000 gallons be enough?
Storage is issue #2. I don't know when things will really go south. It could happen tomorrow. It could be years from now. If you are going to store water you'd better plan on long term since even if it happens tonight,  you will still have winter to contend with. Winter for most of us means freezing. Freezing means the water, turning to ice, will expand, and your 55 gallon drum will have a split down the side. All 100 of them if you stocked 5,000 gallons which is now zero gallons. Burial is one way to protect your water. A ground cover of 36 inches will protect in most places. Northern Canada, not so much, the premafrost runs all the way to the south pole.
The same applies to the 275 gallon totes that many liquids are shipped in. Those are a bit more difficult though as they will collapse if dirt is dumped on them. With totes you will need to provide a lumber structure to shield the container from the top and sides. Old treated lumber will work. Dirt can sift through, but that shouldn't be a problem.
Protection is the last consideration. I already mentioned freezing, but you also need to consider contamination. Bugs, chemicals, and algae top that list. Have a couple of jugs of chlorine handy, that and a filter system. A means to boil the water is also a good thing.
If you think about what our ancestors had, and can find a way to emulate them, you will fare better than most. There is a reason beer and wine were common drinks centuries ago. The alcohol content killed most pathogens, and neither would ferment in the presence of dangerous contamination. That is why shiners want a good clean water supply.
If you are planning on a month of hardship the water in your hot water tank would be sufficient. For a real crisis, it will be a small start and a terrible finish.
Water is essential to life. You can last 40 days with out food, but not even four with out water.
Proper prior planning prevents poor performance.