This is interesting because I grew up drinking demineralized water. We paid for it to be demineralized in a reverse osmosis filter at the supermarket. Most of the people I know drink purified (demineralized) water every day.
According to over 80 studies completed around the world, low mineral water increases health risks for cardiovascular diseases, cancer, diabetes, respiratory diseases or other health problems. It seems that our bodies need dissolved minerals in fluid and cannot effectively use minerals found in food only.
Simply stated, when we ingest demineralized water, our body is forced to re-mineralize it (using stored minerals in bone) before the water can be passed into the bloodstream. When we are done with the water we have no way to demineralized it, and the minerals are lost in the urine. Mineralized water comes into the body already mineralized and leaves the body without robbing us of essential minerals.
Low mineral water is "aggressive" and corrodes pipes, pans, and anything it contacts, attempting to re-mineralize. It is so aggressive that desalination plants are forced to add some minerals to the water after purification -- just to protect their pipes. Low mineral water absorbs metal that it contacts, which we in turn ingest.
Additionally, studies carried out in Texas show that in counties where water mineral content is low, crime and suicide rates rise. The more minerals (and pollutants) in the tap water, the lower the crime and suicide rates. This effect may be related to the amount of trace lithium in the water.
The world health organization has formulated drinking water standards for the third world in order to reduce negative health effects seen in persons using low mineral water. Their standards are as follows:
Total dissolved solids (TDS): Min 100ppm, ideal is 200-400ppm
PH (Acidity): As close to 7 (Neutral) as possible
Calcium: Min 20ppm, ideal is 40-80ppm
Magnesium: Min 10ppm, ideal is 20-30ppm
I've taken a look at a lot of mineral content and total dissolved solids (TDS) statistics for bottled waters and have found two that make the cut according to the WHO. Naya and Evian. All others fall short in some area. FIJI water almost passed, but has only 17ppm calcium. (200ppm TDS and 13ppm magnesium)
Naya appears to be mostly unavailable anywhere in the united states, so our only choice left is Evian, one of the most expensive on the shelf.
Recently I purchased two devices which measure the TDS and acidity (PH) of fluids. They are intended largely for aquarium use but work very well for my purposes. Below are my test results:
Distilled water: 0.40ppm TDS, 6.8 PH
FIJI water: 167, 7.65 (bottle claims 209, 7.5)
Evian: 280, 7.18 (bottle claims 309, 7.2)
Deja Blue: 8, 6.2
Fairfield Tap water: 612, 8.75 -- Tastes like ass.
Hy-Vee spring water: 64, 8.3 -- Tastes like ass too.
New Brita filter, FF tap water: 515, 5.3 -- Britta takes a little TDS out and lowers the PH. Lower PH tends to make crappy water taste better - lemon in your tap water serves similar function. Gives it an acidic bite and makes it taste more "crisp."
Expired Brita filter, FF tap: 510, 7.2
"Washed" Brita filter, FF tap: 573, 6.5 -- One website claimed that buying new filters was a consumerist scam and all you need is to wash the filter upside down for 5 mins instead. Pure BS.
Aquafina: 1.2, 7.34
Dasani: 29, 5.75
Essentia: 49, 7.85 (claims to be 9.4 PH)
Pellegrino: 660, 6.7 (claims 960ppm TDS) -- Interesting that Pellegrino is carbonated but retains a neutral PH. Tooth enamel dissolves at 5.2-5.5 PH, so this stuff won't degrade teeth.
Philips Vodka: 0.20, 7.2
Brita filtered Philips vodka: 27, 5.4 (added TDS and increased acidity)
Bushmills Whiskey: 14, 4.2
Tanqueray Gin: 8, 6.4
Sav Blanc white wine: 690, 3.42
Syrah red wine: 1150, 4.00
Corona Light: 450, 3.9
Bud Heavy: 530, 4.22
Diet Coke: 325, 3.4
Sugar free Red Bull: 120, 3.5