Before people panic, they need to understand some of the basics of water treatment. Nuts pass all kinds of wrong advise after storms. It's the way they get back at society for doing them wrong!
One big thing to keep in mind is that they public health folks drink the same water everybody else does. Does it sounds logical that they will suddenly decide to dump their whole career and poison their family just to kill your fish?
There are very specific rules on the amount of chlorine/ chloramine used to treat water. The water is sampled and tested at numerous sites around the system. How often and how many is designed to make sure the water is good in all locations. Because there is a storm doesn't mean they suddenly stop doing their job.
The chlorine may be higher and people with sensitive noses may smell it. But it is still well within the set limits.
A normal dose of your dechlor is designed to cover the various levels of chlorine allowed.
Does anything on your dechlor product tell you to double the dose after storms? DUH!
Just maybe the people who run things all the time know what they are doing???
In emergency situations, --- don't trust the nuts for info. Trust the trained people!
If they tell you not to use the water, don't use the water. If they tell you it is safe, it is safe.