I've been debating installing a charcoal filter on the tap water supply that I now use for WCs on my various setups. Catalytic carbon lasts much longer if only exposed to chlorine, but the addition of chloramine to the water supply is always a possibility. I also needed to know if I already had chloramine in my tap water.
I've seen chlorine/chloramine test kits available, but haven't been able to find them lately when ordering other stuff.
I've no doubt that I am not the first person to think of this, but I have never seen it mentioned before (maybe I just missed it):
I keep feeder fish--so I can stand to lose some, if necessary.
I set out ~1/2gal of tap water, open top, for 3 days. Then with no treatment what-so-ever: I added 5 minnows and an airstone from my holding tank. I checked on them for 1 1/2hrs--they were fine. No chloramine currently in my tap water.
The chlorine should dissipate in ~24hrs. I gave it ~3 days. The chloramine would not dissipate--so if they were in the water--they would still be there and kill the fish.
Answered my question. Maybe this will help someone else out....