Clean, blue water barrels have been sometimes available for purchase at $40 each at a local Emergency Essentials store because that's also what Walmart was selling them for.
Here's my brother-in-law Todd's approach to storing water. When Todd speaks of "members" below, he's referring to members of the Church of Jesus Christ of Latter-day Saints whose food storage and disaster preparedness programs are second to none (as you already doubtless know or you wouldn't be interested in the web site you're reading right now). A "ward" is a neighborhood of 100-200 families (about 600 individuals) and a "stake" is a collection of 7-15 wards.
"I have been leading a large effort for a year (and continuing for two more years) to place emergency water in nearly every home (including non-member neighbors) in our ward boundaries. And other wards in the stake have done the same. We simply contract to purchase the used food-grade barrels from Pei Wei (with soy sauce) for about $18 each.
"We get groups of men to come to my house and sterilize those barrels with a couple flushes and bleach water. We leave them for several days (rolling daily with bleach water) to purge any residual that may have been absorbed into the poly.
"We also build some small racks that hold the barrels on their sides out of 2×4's and plywood. We install $6 brass spigots in the lower bung. We then deliver racks of 2 stacked barrels.
"This allows every home to have 100 gallons of drinking water available. We've already distributed enough to replace the equivalent of two full water tanker trucks. Plus, since swimming pools are found at nearly every house here, many have purchased the high-end Katadyn filters that can filter 10,000 to 40,000 gallons of pool water (a nice backup).
"My own tests with these water barrels has proven to be very successful. The barrels are filled with fresh water and two tablespoons of bleach and then sealed.
"I kept four barrels in the back of my shop for over four years without rotating the water. When I opened and tested the water last year, the water was pure and good tasting. Water stays pure until it is contaminated. Note that my shop would routinely hit temperatures above 110°! The most important element of storing water in poly barrels is to keep them out of direct sunlight. Put them in the corner of the garage.
"I now refresh the water each year. I have a rack of six barrels (2 stacks three high). Refreshing the water is simple:
"We encourage members to refresh their water and 72 hour kits each spring at General Conference time."
Here is a sample set-up. We got steel frames for 9 barrels, pretty expensive, but it was by mistake and we had to honor what the guy understood we asked. (As pictured, the bottom ones aren't filled yet.) Despite the considerable number of barrels, the space taken up is pretty insignificant and even after 5 years, we haven't regretted it. It's a good idea to pick a special time each year, maybe Labor Day, Memorial Day or another occasion to empty and refill them.
The problem with bleach is that most bleach from the grocery store has detergents or perfumes in it and is not well suited for the application of water storage. There are better systems.