My hubby used to work for a company that leased Reverse Osmosis "pure water technology" to small businesses. He had access to a TDS (total dissolved solid) meter, and we tested the municipal water, as well as bottled water that is sold on the shelf and through delivery services.
Did you know that spring water is treated with chemicals at the source, brought down in big trucks, then processed for bottling? This means lots of water wasted, and the TDS measures higher than some tap water!
After testing every thing we could get our hands on we discovered that for taste and purity the RO unit won hands down. So we have been using the innards of a machine to filter city water. This cuts down on the cost, saves plastic bottles from being used, and gives us access whenever we need purified water.
The RO process wastes some water. We figured out that it takes 6 gallons of city water to get 1 gallon of purified water for use in our household. The other 5 gallons contain higher levels of solids- although it has been charcoal filtered so it is relatively free from chemicals. The "wasted" water is a by-product condensed from the gallon that is pure (it has something to do with the membrane that separates the solids from the water being unable to extract all the contaminates without water getting through).
We use those extra 5 gallons for maintaining our compost pile, washing our car, mopping the floors and watering the landscape portions of our yard - allowing us to cut down on sprinkler usage and water frequency (living in a rental means we cannot xeriscape & xerogarden as I would prefer to.)
We collect the water in used milk cartons that we have sanitized.
The TOTAL cost per gallon for our delicious purified water? 3 cents.
The convenience of not having to cart bottles home and store them? Free!
And of course the impact on helping save our planets resources is priceless.
More to come on this important topic...