Just for the record, the reason I stayed away from RO (never used it for my aquariums, either!) is specifically because of the waste issue. I get 2gals waste/gal pure water, and it only takes a few hours to fill up a 35gal trash can. I used several per week during summer. Creating 2 gallons of "waste" water per gallon of "good" water, to me, is criminal. So, it's going somewhere and I am not just letting it feed the leach field and fill up our septic system.
You've said in this thread that you are on a well hence why I asked if you used softened water. What you've described is still a pretreated municipal water source weather it came from a large well a lake or wherever they are treating that water for you. It is nothing like my well water that I pump directly from the ground untreated.
I think I missed one of your posts, fifty, makes the one following it look silly. GAH! I hate when that happens, it interrupts the flow.
To help clear some things up: I moved to the Sierra Nevada from southern California about six years ago, I'm actually not terribly far from motherlode, by my guesstimation.
Where I moved
from is a city that owns its own very large well. This water is treated only with chlorine because EPA demands it. The water is high pH and high alkalinity, but is otherwise relatively clean, primary alkalinity is calcium carbonate (well rests below a thick bed of limestone). Other than the chlorination, it is very much like water you've just pumped out of a well, it requires no filtration, nothing other than what the government requires, which actually "dirties" this water, the chlorine added is considered a contamination, it's
that clean.
Where I live
now, in the mountains here east of Sacramento, the geology is decidedly very, very different. We have a mix of granite plutons (the plutons are actually floating on the rock below because the granite is lighter, thusly, the Sierra Nevada range is rising NOT because of tectonic motion but because it's made up in large part of floaties!), volcanic lava fields (batholith, IIRC) which, as you may know is comprised of many minerals, and ancient beaches. Honestly, the geology is very mixed, too many soil and rock types to get into. Going over public test reports from areas nearby (remember, this is called gold country for a reason and mining methods have not always been very clean) I see readings for substances like arsenic, which does occur naturally here, lead, and many other heavy metals that have not appeared on reports I've read in my previous location.
The well we currently live on now is just under 800' deep. Rain and other weather patterns have zero affect on the water, which leads me to believe it's being filtered through quite a lot of rock and not just soil or dirt (we live on a heavy, red clay, which just happens to be the color my pre-filter turns, as well as the toilets, showers, tubs, sinks, etc, etc, etc, ad nauseum).
I live about a mile away from a cave maintained by UCDavis that is filled with gypsum crystals. My water turns everything orange, and I believe I mentioned my own testing results of my current well water. We do nothing
more than filter what goes into the house with carbon, a whole-house filter.
Landscape water is done with a line that comes directly from the well and bypasses completely any filtration. Therefore, that water is very hard, not a terribly high EC if I recall, I only tested it once after I got the EC meter, but I took a ppm reading out of our sink, before my husband rerouted the landscape and gardening water lines. Came out at 158, which I thought wasn't too bad at all, but everything I
observe tells me there's more to it than that, as you seem to surmise.