Reddit mentions of ENERGIZER 500 Watt Power Inverter 12V DC to AC + 4 x 2.4A USB Charging Ports Total 9.6A

I know your question was about water, but I'd like to rebut that article in general. I'll make sure to focus on water for you though. (TL;DR: I see The_Prepared is already here, and the article you already found is my suggestion.)

Here, I shall make some useful alternate suggestions:

Article Title: Well, I see the lies have already begun. Hey, I know of an article with almost the same name that's actually useful!

• Pedal power fail socket: Dumb. For that price, buy a solar panel, a decent charge controller, and a battery. Find a nerd if you aren't one, hook them up (safely, standard internet advice disclaimer here), and you get power without needing to pedal, and also storage. If you want to charge your phone, use a 12v adapter, and if you need 120v power for something, you can get an inverter. It's pretty easy to hook it all up, there are a lot of resources, search for "DIY solar generator". Here's one I made for a good friend. This will be about a hundred times as useful to you, at only a slightly higher price.
  
  
• Crappy GMRS radios: You can tell this article is BS because they actually think the "23 mile range" claim has some kind of validity. Emergency comms for preppers generally means a Ham radio license, those walkie talkies are only marginally better than toys. All the same, they're cheap, and can't hurt. I have a pair.
  
  
• Cell phone: It amuses me that the article states "we have a strong suspicion", thus confirming they did no actual journalism or research . In the event of a disaster, 2G will be exactly as non existent as it is now. They also chose the Nokia because of a meme! What's their next memetic indestructible suggestion? A Wiimote? Gamecube? At least you could bludgeon an intruder to death with a Gamecube. My suggestion: Use your regular phone, because it works with the existing infrastructure. Text messages tend to work better in disasters, because high call volume stresses the network, and texts are a tiny amount of data. Also, stay off the phone unless you really need to use it, because someone else might be in a life threatening situation and need to call for help.
  
  
• Ultimate survival kit: I disagree with premade survival kits because they use low quality items, most of them won't actually be useful, and if you build your own, you have more familiarity with the equipment and usage. If you want a pre made kit, look at the contents, buy it in pieces, and test every piece before you put it in your kit. At least then you'll know how it all works, and be familiar with exactly whats in there.
  
  
• Glowy keychain thing: I mean, i like glowy things, but the only real use for this is if you want to take a photo and post it on /r/EDC and then get flak from them because it's not even tritium, which incidentally doesn't need charging and would work far better for the purpose the article suggests anyway.
  
  
• Waterbricks: No argument here, but The Prepared has a really awesome article about this and I'm not going to type words that they have already covered in great detail. (I see they've already found this thread, anyway.)
  
  
• Condoms: Pretty fair point there. They expire, so rotate them like any other perishable prep item. I'd say probably stock conventional ones because no one wants a hurricane baby, and some unlubricated ones for assorted other purposes, but don't plan on using them for stuff. If you need something waterproof, do not think "I'll just put a condom on it when I need to!". If you can think of it in advance, figure out a proper solution, and leave the condoms for in a pinch fixes you didn't anticipate.
  
  
• Hand crank radio: Sure I guess? I'd rather have a radio that uses rechargeable batteries, and then use the solar rig from my first bullet point to charge the batteries. Anything with a hand crank will put out a really tiny amount of power and requires you to effort. Once you stop cranking, you're running off of the way-too-tiny battery in the unit, whereas solar is a huge amount of power that requires no effort, which you can then use to charge lots of batteries and then just swap them. Or run the radio off of a 12v adapter directly. For the radio itself, You want AM/FM/NOAA Weather Radio at a minimum, and an argument could be made for shortwave, because it can cover huge distances (I'm in central Alberta, Canada, and can easily pick up Radio Havana Cuba on shortwave). Again, a Ham license and some equipment of that sort would also be useful if you want to get into that.
  
  
• MRE's: Sure, though ask a soldier friend what they think of them, and what they do to your guts. I'm personally going to stick with Mountain House or similar. Also, there's an article from The Prepared on this topic, too. (Hey mods, just so you know I'm not paid or coerced in any way to suggest this site. I gain nothing from them, it's just the best information I've found, and it's convenient to link them instead of type a whole lot.)
  
  
• As seen on TV "Tactical" Flashlight: No! Ask nicely in /r/flashlight, or pick something that meets your needs from Here. Thrunite tends to be inexpensive, high quality, nice features, and nice light, if you're looking for a brand suggestion. Fenix and Nitecore are also solid choices.
  
  
• 1911: Limiting this one because too much politics and heated debate. I love 1911s, but .45 is a bit big for an infrequent shooter, but a 9mm clone like an STI Spartan, or perhaps a Jericho (Baby Eagle) in 9mm, or a CZ, would work nicely.
  
  
• Casper Mattress: Wait, that's an ad, never mind. I couldn't really tell the difference.

This is basically what I have. I bought a different battery and inverter because I have an account at batteries Plus but this is a widely accepted quality battery and a decent inverter. I would recommend buying at least the battery local as shipping them is expensive.

NOTE I did not include fuses/breakers in this list but you definitely should build these into your design.

https://www.amazon.com/Renogy-Watts-Volts-Polycrystalline-Starter/dp/B00DCEKKQ0/ref=sr_1_2?ie=UTF8&qid=1487256044&sr=8-2&keywords=renogy+100w+starter+kit

https://www.amazon.com/Trojan-T27-AGM-Group-Purpose-Battery/dp/B00NY0RAW4/ref=sr_1_1?ie=UTF8&qid=1487256242&sr=8-1&keywords=trojan+12volt

https://www.amazon.com/34-97-2-15-17-ENERGIZER-Inverter-charging/dp/B01N5LUMDF/ref=sr_1_16?ie=UTF8&qid=1487256346&sr=8-16&keywords=500w+inverter

Depending on what you really want to power this may be way more than you need. You really should start by figuring out the load you want to power and then design your system around that number. This is a great little tool for figuring out how much power the devices you want to power will use and it's certainly cheaper than buying too much system and finding out you could have done what you wanted with half as much as you bought.

https://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU/ref=sr_1_1?ie=UTF8&qid=1487256555&sr=8-1&keywords=killawatt

I'm certainly not an expert at solar but am learning so feel free to PM any other questions.

It would be pretty easy to build something similar for a lot cheaper. Pick up a used suitcase at the thrift shop, mount a 50w panel on the outside (much better than the 10W panel in the case you linked to.) Inside the case, mount a charge controller with USB, this 20Ah battery (again, better than the 16Ah in the other one), and this 500W inverter (not sure how big the one in the expensive case it, but 500W should be enough.) So for less than $250 and a little bit of build work, you can have a much more functional system (500% larger solar capacity and 25% more battery capacity).