[ohthanks]

Carbon filtration will not remove dissolved solids (lead, heavy metals) without added ion-exchange resins. RO is generally the most effective broad spectrum treatment method for drinking water.

The mineral issue is pretty much bunk, if the lack of trace minerals in your water is a concern you need to see a doctor. Food is your body's preferred source of minerals, you have to drink a lot to have much effect on your daily mineral intake.

The waste water is real, 4 to 1 is about average, it can be improved but it's pretty unavoidable in the process. They are water using appliances, we use 20-40 gallons of water to wash a load of clothes and most people don't think twice about it.

[prions]

I'm a water treatment engineer. Carbon filtration will remove dissolved solids and heavy metals, and with high efficiency if done correctly. Most GAC columns designed to remove lead and heavy metals are enriched with sulfide ions to increase the removal efficiency as well. People prefer to use ion exchange resins to remove heavy metals because they can be regenerated more easily and efficiently. Also ion exchange resins allow you to recover any absorbed minerals.

http://ascelibrary.org/doi/10.1061/%28ASCE%290733-9372%28199...

[raddad]

Carbon filtration doesn't remove fluoride, does it? (Or arsenic) The only water filtration system I have found that removes fluoride is the Berkey brand. I've not seen any filtration systems in the stores even mentioning fluoride or arsenic.

Berkey filters http://bit.ly/1WdBneq (Edit to add arsenic and Berkey link)

[ohthanks]

This is totally correct. It is also not very applicable to drinking water & whole house systems that homeowners are interested in.

There are carbon cartridges with ion-exchanges resins blended into the block that seem to be effective for lead removal at low flow rates. They tend to have lower flow-rates and capacity than is ideal.

[rdl]

What home products would you recommend, either flow-through pitcher style or faucet or whole-house?

[matthewbauer]

Why is the mineral issue bunk?

According to this WHO report[1], it seems like a real concern:

"Low-mineral water markedly: 1.) increased diuresis (almost by 20%, on average), body water volume, and serum sodium concentrations, 2.) decreased serum potassium concentration, and 3.) increased the elimination of sodium, potassium, chloride, calcium and magnesium ions from the body. It was thought that low-mineral water acts on osmoreceptors of the gastrointestinal tract, causing an increased flow of sodium ions into the intestinal lumen and slight reduction in osmotic pressure in the portal venous system with subsequent enhanced release of sodium into the blood as an adaptation response. This osmotic change in the blood plasma results in the redistribution of body water; that is, there is an increase in the total extracellular fluid volume and the transfer of water from erythrocytes and interstitial fluid into the plasma and between intracellular and interstitial fluids."

It might not be enough to outweigh the benefits of highly filtered water, but just because you have enough minerals from food doesn't mean that minerals in water aren't having an effect.

[1]: http://www.who.int/water_sanitation_health/dwq/nutrientschap...

[Laforet]

This particular report cites a number of rather fringe sources as well as many non-English journal artiles that cannot be easily verified. Overall I find the author's conclusions hard to believe.

>It was thought that low-mineral water acts on osmoreceptors of the gastrointestinal tract

This is not how osmolarity sensing works.

[thescriptkiddie]

Sorry, but you really don't want to be drinking true deionized water. It isn't a about long term mineral loss, it is about the immediate discomfort of drinking it. It's fine for the first cup or two, but after that it starts to burn. Wash your hands with it and you'll find you skin is dry and cracking. You'll notice that reverse osmosis systems intended for producing drinking water have a much lower standard of purity than those intended for, say, washing glassware. If you want to make sure there is no lead in your drinking water a carbon filter with an ion exchange resin stage is the way to go. But really, get over it, 99% of the US has safe tap water.

[Laforet]

>It's fine for the first cup or two, but after that it starts to burn. Wash your hands with it and you'll find you skin is dry and cracking.

I have handled and, against my better judgement, quaffed many types of deionised water: triple glass distilled, reverse osmosis, ion exchange, etc. They taste more or less the same to store-bought distilled water and I have not yet had any of the ailments in your complaint. There is also a certain coworker who developed a pechant for the MilliQ water machine and regularly filled her drink bottle with ultrapure (>18.2 megaohms) water there. Suffice to say she is still doing it.

>But really, get over it, 99% of the US has safe tap water

This is not necesarily true given the state of water infrastructure in the US. The water leaving a treatment plant is not the same as water coming out of a tap.

[coryrc]

Water departments are supposed to do surveys at residential taps to evaluate the effect of alkalinity on lead in the water as it is actually drank. Even the small town I came from does. Seattle, for example, made some changes based on these surveys: http://www.seattle.gov/util/MyServices/Water/Water_Quality/W...

[makomk]

Water departments have been cheating on those surveys to get the right results. That's one of the causes of this scandal.

[thescriptkiddie]

For what it's worth, I could be mistaken. The storebought deionized water I get could be contaminated with carbonic acid, which would explain the burning.

[Laforet]

Distilled water tends to exhibit an acidic because there are nk dissolved salts to buffer against atomspheric carbon dioxide which forms carbonic acid once dissolved. However I would be very surprised if store bought water contains enough CO2 to irritate human skin, unless you meant carbolic acid instead of carbonic acid.

[iofj]

You will notice the taste difference though.

[ohthanks]

You will for sure, I actually like it but not everyone does. You can remineralize and change the taste without too much trouble. I would avoid any other claims made for that process but it does usually improve the taste. Straight RO water is not great for coffee or tea as well.

[IndianAstronaut]

Where does the average person find RO water?

[HeyLaughingBoy]

Go to your local aquarium/tropical fish dealer and ask. They'll be able to list pretty much all the providers within a reasonable driving range.

Also lots of cities/towns have RO water providers that will sell anywhere from single gallons to thousands.

source: used to be a marine aquarium hobbyist and bought thousands of gallons of RO water to make seawater.

[ngoede]

Some grocery stores and walmart's have RO water machines outside their stores also. However, if you choose to use those it would be good to invest in a tester as they do not always change the filters on schedule.

[ketralnis]

Any drug store will have distilled water

[elijahparker]

I use RO with a mineralization filter stage and absolutely love the taste of the water. I'm using the 7-stage RO system by iSpring.

[ktRolster]

And for an extremely cool experience, try black water: http://getblk.com/

For varying definitions of extremely

[mirimir]

Sounds like swamp water ;)

[ktRolster]

It actually tastes like......bottled water.