posted 13 years ago
I have a well with pressure/volumefor 10 homes. I also have a backup spring fed line that I use mostly for irrigation, which I dont need much of. many elements, single function, etc/
giardia life cycle includes a gut incubation and spwan, so the most likely way to get beaver fever is shit to mouth disease- animals shit in water and then somebody drinks it. boiling the water is one simple but energy intensive way to deal with giardia and other protozoan waterborne ailments- which, until the 1890-1920 creation of municipal water supplys, were responisible for more deaths annually in the US than car crashes are now- over 100K in chicago alone in the 1890's. diptheria, malaria, etc...
most of the these dangerous critters are anaerobic- they dont need to breathe. to kill these buggers, boiling (7 minutes min, think same as hardboiled egg) , filtering (2 micron is max size for bacteria like giardia), pressurizing (ever try to compress water?) and finaly chemicals (iodine, 25 minutes use vitamin c powder to help nutralize bad taste) are the way it tends to get dealt with depending on local resources/wealth.
now there are virus as well. the filters get pretty hard pressed at that scale, but I hear carbon ceramics in the .2mc range are available that can do it. of course, boiling and iodine are options.
note on iodine, cholorine etc: the water you tap needs treated, in sink or on stove, not the source! just to be clear. if you want to treat the source, theres a whole other GREAT set of things to do, and they revolve around assessing the biological state of the spring site for variuous indicators, and then adjusting the biological assembly at the pre-system intake towards clean water by introducing more filter plants and indicator species (ie, cattail suck up anything, and a few local minnows known to require high oxygen cold temp water- when we had a direct line from the stream, we had brooke trout in the pond...had to be clean. a flood in 97 blew my high road and pond out and I havent rebuilt as the low road works fine. interesting to watch the stream side morphology adjust...anyhow, that preintake filter design angle is a great one and there are folks doing interesting work there.
once the water is in system, I prefer a 20mc and a 1mc filter.
if you know your ground source, have it tapped direct and no mammals can poo in it, and use a good filter kept clean, youll be fine. unless they frak your valley, there are major local tectonic/hydromorphological shifts, industrial forestry practices happen next door, or you endure large hydrocarbon spills. good luck!