My water sourced from EBMUD uses chloramine per the water report. I use the boogie blue+ filter which is a carbon activated filter, which removes up to 87% of chloramine compounds. If i have time i try to let the water sit for a while and aerate it for a few hours. I read an great article online which i can't find, someone had done some experiments and found showing half-life of the chloramines to be about 7-10 days, and also stated aerating the water causes the chloramine compounds to break down faster, though that was not part of the experiment.
The filter is also probably taking out the other minerals. I only use organic inputs and amendments, and aerated compost tea and seed sprouted tea, so micro-life is important to me, which is why i try to remove as much chloramine as possible.
Ive heard of using vitamin C powder to remove chloramine, though im not sure if that would be organic, but it is mostly derived from corn as ascorbic acid. I know there are organic sources for vitamin C but i have no idea if they react the same way ascorbic acid does with the chloramine compounds.
I also think you need to re-PH your water if you use ascorbic acid, though im not sure how far off it brings the PH down and obviously whatever PH fix would hopefully not harm micro-life either. Though PH is not that big a deal when growing organic living soil techniques but i wouldn't think you'd want PH to be way off.