Our drinking water is treated with chlorine in order to protect against microbial contaminants. Because there is little else in our water that produces a taste or odor, the chlorine is often the only taste remaining. Seattle tries to add just enough chlorine so that it is still detectable at the end of Seattle purveyors distribution systems. Most times, the chlorine leaving their treatment plants is 1.5 mg/L, and the average chlorine concentration in the distribution system is 0.8 mg/L. This is well below the maximum concentration allowed in drinking water, which is 4.0 mg/L.
Chlorine taste and odor can be minimized by either letting water sit overnight, or using a carbon filter. To let the water sit overnight, collect a fresh sample in a clean container suitable for beverages, loosely cover or cap it, and store it in either the refrigerator or on the counter. Carbon filters are very common in either a pitcher or faucet device. It is best to use a filter that has been NSF certified for removal of chlorine. If you do use a filter, make sure you change it according to the manufacturer’s instructions.