I have water that comes out at 12.5 from my well, and if I dont treat it, the water will kill my plants in organics. Does it every single time. If you have 9 or under ph I wouldn't worry about it, but if you live in a area with lots of limestone and ph over 12 you better do something about it before you use it.
Trust me, take it from someone with super alkaline water. I can either filter (and let the soil easily adjust the RO water) or adjust the ph. Either way they will do fine... but if I dont do either they WILL die. I cant water my lawn without it being treated or it will kill it. Come get some of my water out of the tap, dont filter it or adjust it and we'll see how well they do. They'll be dead within 2 weeks.
well obviously if your water is that alkaline and you keep flooding the soil it won't work. Are you drinking from this well? what else is in it?