There some things not mentions but may help to give you hope. One is the question of chloramine or chlorine used to treat the water. If you are lucky enough to have only chlorine in the water, the five hours will have let a fair amount of it gas off. You may be able to judge the difference when you drink water. If it smells strong of chlorine, it quite likely is rather than chloramine. One advantage of using chloramine from the treatment angle is that it does not gass off nearly as quickly. They can add less at the start and still keep the chlorine residual readings up to required levels.
If your supplier is large enough, there will be a consumer confidence report that tells which is used to treat the water. Larger companies are required to post it online. A quick search might tell you a lot about the water.