posted 12 years ago
Chlorine will off-gas rather quickly when exposed to the air.
Yes, chlorine will off-gas, given enough time. However, many municipalities are switching to chloramine, a combination of chlorine and ammonia. This compound remains stable and an effective antimicrobial for much longer and simply setting your water out for a few days will not appreciably reduce the amount of chloramine present in the water. Check with your water provider to ascertain which they are using, chorine or chloramine.