Make sure to read the labels of each bottle to determine the type of water and be aware of products that may look like water but contain juices, flavoring and sugars. For municipal tap waters be sure that the water supplied to the location is billed by the local municipal water department. Make certain that the location does not have any treatment devices such as water softeners, reverse osmosis equipment or activated carbon filters. A tap on the side of the building often yields water direct from the delivery lines and will give a representative sample. Do not use water which passes through a plastic hose as it will retain a strong plastic flavor.
Water heaters can alter the character of tap water.
Run the cold water tap for at least one minute prior to rinsing the bottle and filling. This will clear the lines of any sediment or flavor the water might otherwise pick up in the pipes. Vigorously shake the bottle and then empty the water. Then fill the water to the top of the neck and close the cap. When the sample is collected store in a dark, cool place away from any petroleum, chemicals or strong smelling substances.