Here is my $.02 with water. How I used to do it and how I am doing it now.
I started storing water when I found a water cooler brand new at a thrift store for about $50. It still had all the plastic wrap on it and had never been used. I found a local "culligan" water supplier (Taylor Water) who sells 5 gallon jugs for $5 if you pick them up yourself.
They take a $6 deposit on the jugs, which is actually CHEAPER than buying them. If you never return them and use them yourself, you just paid $6 for a 5/gal water jug.
I started out with 4 jugs, and every time I made a return trip to exchange the empties I would add one or 2 more jugs to my collection by paying the deposits on them. It took some months, but eventually I had 50 gallons (10 jugs) of drinking water stored in my basement.
I eventually got to the point where I had 20 jugs in storage — and would make an exchange run whenever I got to less than 10 jugs (rotating them) so my water supply would fluctuate between 100 gallons after a refill and down to 50 when I was "empty" Water exchanges were around $50 but I was flipping them every couple of months, sometimes 3. AND having the extra meant that I had some leeway with the dates of making my refills (since the place closed at 4:30PM and is almost impossible to get to easily).
At some point my son's doctor told us he had too much lead in his system (he had been drinking tap water at his mom's house for a long time). I decided it was a good time to get the Berkey Filter I wanted — so I bought the Big Berkey stainless Steel 2 gallon unit. I also got the PS2 fluoride removal filters (they came with it as a package deal).
I wanted to keep the water cooler and 5 gallon jugs and just move to filling them with the Berkey filter.
This was a problem because the Berkey filter takes a LONG LONG time to filter 2 gallons and filling 20 5-gallon jugs would be a project I am still working on today if I had done this LOL. They DO make permanent caps and re-usable water cooler caps for standard 5-gallon jugs though so that was always a valid option.
At some point trying to figure out how I was going to use the water cooler and 5-gallon jugs (having instant hot/cold water was always nice to have) — but we were moving and realized we did not have room for them. We opted to sell the water cooler on craigslist (I got $65 for it and made a $15 profit after using it for 4 years). We returned all the jugs to the water cooler place to get our deposits back ($120 for 20 bottles) which ALMOST put the money back in our pocket for the Berkey system.
NOW what I am doing is taking empty 2 liter pop bottles and filling THESE with the Berkey system. I find that I can fill a bunch of 2-liter bottles easily. We keep the Berkey in the kitchen so it is right there when we cook and we take water directly out of the spigot. We keep a bottle in the fridge, we keep a couple of STURDY (formerly Arizona Tea) 1-gallon jugs filled with cooking water in the kitchen as well.
The 2 and 3 liter pop bottles are almost indestructible. We go camping and my 2 year old will take one and THROW it everywhere, against trees, rocks, stomp on it, and just abuse the hell out of one and it will NOT leak, or break. I've shown my friends how sturdy they are by throwing them as hard as I can against a tree and they just bounce off. They are designed to withstand a LOT of shock and pressure.
1 gallon plastic "milk" jugs from the grocery store containing water however… THEY SUCK.
I've dropped them on GRASS from waist height with no extra force to have them explode open on me. They are fine if you have them in your fridge or on a storage shelf, but they are not durable enough that I would keep them in my truck's toolbox or a vehicle trunk.
Some of my 2 liter bottles are over a year old now and have been kicked around more than you can imagine — a little soap and water and they are as good as new.
It is taking a long long time to get back up to 100 gallons but the last time I counted — I am somewhere around 60 liters in permanent storage with a few gallons floating around here and there.
So I basically have 15 to 20 gallons stored. It will take another year at this pace to get up to 50+ gallons (how quickly I gain empty 2 liter bottles and have time to clean / fill them).
In my opinion once I have enough bottles in rotation where I always have 100 gallons of clean drinking water — transporting them is MUCH easier than trying to lug around 5 gallon water jugs. In a bug out situation, you can transport 10 2-liter bottles (a little more than 5 gallons) in a much smaller space than you can transport a single 5 gallon jug.
Having a couple of portable water filters (Big Berkey and a Katadyn Hiker pump) means we do not have to be quite as concerned about having that much water in backup — but it is always good to have.
It has already come in handy this year when the water company was replacing the water main on our street and we would go through long periods without water every day of the week. We always had plenty of drinking and cooking water so it never became an issue.
My son's lead was down to undetectable in his bloodstream within a few months after using the Berkey water filters as well and I believe the quality of water is much better than anything BOTTLED — including those 5 gallon bottles.
It will probably be another year before I replace the PS2 filters, and another year from there when I replace the charcoal filters, so the replacement costs are definitely worth it. The taste of the water is superb and over time I've gotten to the point where I can detect anything that isn't pure in the water I drink, even small amounts of whatever is left over and not washed out of a 2 liter bottle that I washed out with soap and water, then rinsed over and over again until there is no soap left LOL. I can tell how many times the bottle has been re-used based on the taste LOL.
There are definitely issues about storing water and drinking out of plastic bottles, but that would be for a different thread.