Ahh ok, that sounds about right, I think the water temp has a similar effect of inhibiting nutrient uptake. I also use tap for my plants though and dont really have a problem but Im in ON Canada. What i do is turn the hot water on full till it just starts to turn warm, crank the cold and then turn off the warm. On the second jug I only need a few seconds of hot once the hot water line is primed but I do the same, crank it then cold, then turn off the hot. This time of year once the cold water lines have flushed themselves by running the water is frigid, so I cant just water my plants with it. After doing the part hot water thing I leave the jugs to sit for an hour or so. This helps to allow the chlorine to break down a bit, but isnt entirely necessary. If youve got higher levels of chlorine in your tap and want to still use it, you should be able to fill jugs up and leave them for a day or so. The chlorine should break down enough to water your plants, although there could be other issues with the water as well.