Water is by far the largest component of your beer - either by volume or by weight. The mineral content of your brewing water as well as the pH have a huge impact on the taste of the product you produce. Here in Portland, OR we have been having quite a discussion over some time about the local water used for brewing. We watch for the water bureau analysis to get information about the mineral and anion content to determine what, if any, adjustments to make.
Specific to your question about chlorine and chlorimine we recently received this in an exchange with the water bureau after we noticed a sudden change in "chlorine taste" in the water.
Water Treatment
Water is first disinfected with chlorine, entering the
system at about 2 parts per million. At the end of the
disinfection process, sodium hydroxide (NaOH) and
ammonium hydroxide (NH4OH) are added to the
water. Sodium hydroxide (at a dose of 3.5 to 5.0
ppm) is added to raise the pH slightly (approximately
1 pH unit). This helps prevent corrosion of household
plumbing and lowers the amount of lead and copper
that can leach into the water. Ammonium hydroxide
(aqueous ammonia) is added (at a dose of about 0.35
ppm as NH3-N) to form a long-lasting chloramine
disinfectant residual. Chlorine and ammonia are used
in a ratio by weight of approximately 4.5 to 1.
Chlorine can be boiled off and filtered out with a charcoal filter. Chloramine cannot removed be easily with a filter and cannot be boiled off. To remove it you are advised to use campden (Potassium_metabisulfite I believe). As noted in an earlier post, the amount used is dependent upon how much is in your specific water. In our water, 1/2 tablet will treat 5 gallons of the local water.
In all cases, less adjustment is better and proceed with caution. Adding salts will affect not only the pH (which is critical for the mash) but also the taste. I am not a chemist and cannot advise you on adjustments. The best advice I can give you is to think about the effect on pH first and taste second. Again, proceed with some caution. If in doubt, use bottled water.
Regards