Chapter 19 - Water Purification

Recently, while responding to an inquiry about collecting drinking water from the roof of a house bus, I had the opportunity to launch into a fairly detailed sermon about water quality. Here, for your pleasure and education is the body of my knowledge on the subject:

While it's unlikely that water from a reasonably clean roof would be any nastier than what comes out of city water pipes, those of us who live in portable dwellings are likely to meet up with a variety of unknown water conditions, from contaminated well water, water drawn from pipes or tanks which may contain impurities, hose bib connections which might have been used for chemical or sewage system cleaning, or even ground water in the back country which looks clean enough for domestic use. Sometimes it's necessary to use water wherever you can find it, but if you want to be certain of it's purity, run it through a proper filter first.

By proper filter, I mean a water purifier, such as a ceramic-coated carbon block filter. The hardware store pleated or spun fiber filters will only remove particles. The carbon granule filters they sell for taste/odor removal are next to useless as well. A true water purifier will remove chemicals, heavy metals, pathogens, pesticides, bacteria, both dead and alive, and any other stuff that you shouldn't put in your body. Most carbon block filters are tested to remove 99.9% of unwanted impurities.

There are several good filters out there, some are quite expensive, such as the Multi-pure, which is often sold through multilevel marketing schemes, and the markup is outrageous. I bought mine from a distributor, and it was still $325.00 (USD) Although the filter cartridges themselves are not overly expensive, the canisters which hold them are specialised, and must be used in order to utilise this brand of filter.

My all-time favorite system is comprised of a standard hardware store cartridge-type filter housing with a Doulton ceramic carbon block filter inserted instead of the pleated or carbon granule filter cartridges that the filter is usually fitted with. The filter housing shouldn't set you back more than $25, and the Doulton filter is about $40 (all USD). If you buy online or mail order, be sure to specify the proper 'candle' (that's what the manufacturer calls them) for a standard filter housing. A few bits of polyethylene tubing, and a dedicated spigot and you're in business! You can pay for the fancy filter-type spigot, but I just went down to the salvage parts store and bought a nice old single unit off of an antique lavatory, the kind with separate hot and cold taps, works just fine and has the proper look for my Housetruck's interior.

Although you could probably scoop water out of mud puddles and get crystal-clear water out of this filter, I recommend putting the standard pleated or spun-fiber filter ahead of the ceramic filter, it catches the large pieces of rust, scale, etc. This requires a second filter housing, but keeping the crud out of your water heater alone is worth the cost. Remember that the ceramic filter will have a definite life span, so you will want to use it only for drinking water, and use the water that comes out of the pleated filter assembly for washing purposes, reserving the purified water for your own consumption.

Water can also be purified by reverse osmosis (RO) process, but this removes much of the minerals that are beneficial to good health, and RO filters waste two gallons of water for every one gallon they make. A pressurized water system is also required. In the case of very polluted water, a RO filter followed by a carbon block filter has proven to be very effective.

For readers without pressurised water systems, some very good gravity-operated filters are available, some which resemble a water pitcher with a carbon filter fitted into the lid. Outdoor equipment stores sell small hand operated pump filters that can be trucked into a back pack.

Note that if your water system uses a "water softener", you should install any water purification devices before the softener, or they will be rendered inoperative almost immediately.

As for using water purification tablets, I'd pass unless it was some kind of emergency. These are usually concentrated chlorine, and perhaps other chemicals, intended to kill bacteria in the water. Personally, I'm trying to consume fewer poisonous chemicals, not more, and dead bacteria are as unpalatable to me as live.

I've been drinking purified water for over 20 years, and enjoy splendid health. I won't even touch the stuff that comes out of city pipes, one taste of the chlorine and I spit it right out (well, sometimes I'm a bit more polite, especially if I'm in a restaurant).

Gotta go, I'm getting thirsty just thinking about it...