alice, thanks so much for the detailed answer. I have *no* knowledge in this area so I really appreciate the background. This is what they say about the technology (on the "technology" page): ZeroWater has four technologies designed to remove contaminants from multiple categories. These four technologies are utilized in a five stage filtration process. STAGE 1 * A 20 to 50 micron filter designed to remove suspended solids such as dust and rust that make your water appear cloudy. STAGE 2 * A two component, dual layer, system designed primarily for organic contaminants. STAGE 3 * A water distributor screen that also removes suspended solids. STAGE 4 * Speciality resins designed for inorganic compounds, such as metals and nonmetals, as well as radiological contaminants. STAGE 5 * A 1 micron filter designed to removed suspended solids. Would stage 4 relate to the fluoride removal process? I'll also be looking for an activated alumina system...

I agree with MichaelsAd that reverse osmosis is the most effective way to filter drinking water. Our problem, as I stated above, is that DH believes this wastes a lot of water. I also agree with dcarch that distillation removes impurities with boiling points above that of water (212F at sea level). That leaves most petroleum distillates which are a problem for our water supply. There are stories of contamination of our underground water by leaking fuel tanks. Distillation would do nothing for this kind of problem, where the contaminants have BPs well below that of water. These impurities can be very dangerous indeed. However, for anyone considering water filtration or softening, I strongly second the standard advice on the plumbing forum. Have your water analyzed before doing anything. Know what you are dealing with. You may find that the impurities in your water are harmless. They may not make your water taste good, but are not dangerous. Iron compounds are one example. The city of Bath in England has been famous since Roman times for its water which contains high levels of iron and other minerals. When I drank it (they charged 50p for a glass!) I didn't like it at all. And it made horrible tea. Water hardness is caused by calcium carbonates which are beneficial to many people. They also leave deposits in pipes, which is why some install water softeners. When we lived in Massachusetts we had no need for a softener, though lots around us had them and worried about the very low levels of calcium in the water. Sorry, I just don't get the hysteria. Cheryl This post was edited by jadeite on Tue, Jan 15, 13 at 9:30

You can remove the iron/manganese and leave the hardness. There are a variety of methods for iron/manganese removal. The best method for your situation will depend on the complete analysis of your water, usage, well output, space available and budget. Here is a list of the possibilities to get your research started: Oxidation/Filtration: An oxidizer such as ozone, air, or chlorine may be used to react with the iron and force it to become particulate iron that can then be removed via filtration. A typical setup would involve the oxidizing unit, a holding tank, then a media filter. This type of system works quite well, but takes some expertise in sizing - you would want a water treatment pro that you trust to help you with this option. Oxidizing filtration media: This type of treatment consists of a sealed tank filled with one of several media. Water passes through and is oxidized and filtered by the media. These are relatively easy to operate and what I would recommend for the average homeowner. There are several different media that can be used: manganese greensand: water runs through for treatment. The media must be regenerated with potassium permanganate. Care must be taken with dealing with potassium permanganate as it readily dies organic material, such as your skin, a purple-brown color. Some people are quite comfortable dealing with the chemical; others are not. Synthetic greensand: This is essentially the same as option (a) but consists of a coating of greensand on a silica sand core so does not require as much backwash flow. Service flow rate is 2 - 5 gpm/sqft. Backwash flow rate is 12 gpm/sqft. birm: This media acts as a catalyst to force oxidation of iron. While it does not need to be regenerated, it does need fairly high dissolved oxygen in the water. If your water does not have adequate dissolved oxygen (and it probably doesn't since it is well water), air injection would be necessary prior to the birm. Additionally, birm requires a minimum pH of 6.8.. Service flow rate is 3.5 - 5.0 gpm per sqft. Backwash flow rate is 11 - 20 gpm, depending upon water temperatures and desired bed expansion. pyrolox: an ore that oxidizes then filters the iron out. It does not need regeneration, but needs to be backwashed (to rinse out the iron) at a high rate. pH range is 6.5 - 9.0. This type of filter works very well, but backwash is critical. Service flow rate is 5 gpm/sqft. Backwash is 25-30 gpm/sqft. Backwash daily. Terminox: Similar to Pyrolox, but a proprietary formula . It does not require as much backwash flow rate and is more resistance to a low pH. The particulars are only available from the company that sells it. Backwash daily. Filox: Also similar to Pyrolox. pH range 5.0 - 9.0. Backwash flow 12-15 gpm/sqft. Service flow 6 gpm/sqft. It must be backwashed daily.

It is very interesting reading this. It really seems like a different beast between Moisture Plus oven in the US and Moisture Plus oven in Europe and Australia. Moisture Plus in the US seems to be plumbed only and there is no mentioning of descaling in the manual, even. Moisture Plus in AU, H 6860BP for example, is a non-plumb model which has an intake straw that user feed it with a cup of water before using Moisture Plus feature. There is a descaling program built-in and process is similar to combi steam oven. I usually think of H 6860BP as a smaller version of H 6880BP in the US, but there are quite a few differences in terms of features. 6860 Manual is here if anyone is interested to read. To address such requirement, perhaps an inline filter just for the oven would work.