Question:
I am interested in any people who have installed a whole house water purification system (i.e. distillation, reverse osmosis, etc..). I want to filter my water down to the micron level (for water-borne bacteria, as well as lead).

Has anyone installed one of these that can provide insight into installation, cost, satisfaction, etc...? Also, who sells these

Answer: I am a water treatment dealer and maybe you don't want my opinion but here it is for others. What you are asking for (whole house RO etc.) is overkill, and when you get the price ($10,000 maybe) and space requirements (150-750+ gallon storage tank for one) you may change your mind. Additionally, the water produced by the systems you mention may not be to your liking if you get the system you describe.

Individual pieces of equipment, no more than needed is what I'd suggest. I.E. a sulfur/iron/acid neutralizer filter, a softener, and an ultra violet light. That is "whole house" (point of entry {POE}). Then followed (at the kitchen sink etc.) a drinking/cooking water separate faucet (point of use {POU}) filter for chemicals/metals etc., or RO or multi-stage filter. Cost installed will range from approx. $1800 up to $4500 depending where/what you buy. This way you won't be "eating up" your plumbing with acidic RO water or mixing raw with RO water to prevent this from happening. The maintenance/operating costs is/are negligible and you get the water quality you wanted without the problems of the type of equipment you originally asked about. Filtering bacteria requires .5 micron or less and will constantly plug up with invisible "dirt", and drive you and the dealer crazy to boot. You don't filter bacteria on the whole house type installations, you "kill" it with chlorine, ozone, UV light etc.. I didn't mention distilled because I know of no POE distillers, which would (like RO) require a storage tank and re-pressurization pump and pressure tank.

You should not buy anything without a water analysis and specific equipment proposals from 2-3 dealers. Select equipment from the dealer that tends to know the most about all types of equipment and treatment methodologies rather than just what s/he sells.