For some reason you dont drink tap water and instead you buy or pour the one from the plastic packaging. Look at the triangle and the number printed in the middle. You may discover some shocking things. You are interested in the water composition but you ignore the chemical composition of the packaging. At the bottom of every packaging look for the triangle with the number in the middle and find out how dangerous is the plastic you hold.
1 PET (often PETE)
These bottles in the majority are intended for single use. There is possibility that they that emit heavy metal antimony, a chemical substance EPA, which interferes with the action of hormones. Also they might be cancinogenic.
2 HDP (sometimes HDPE)
This is good plastic which has the lowest probability that will emit chemicals in the water.
3 PVC (sometimes 3V)
It emits two toxic chemicals and both have influence on hormones in the human body. Besides this it is the most commonly used plastic.
Plastic which doesnt emit chemicals in the water. But most commonly is used for making plastic bags instead for water bottles.
One of the good plastics, usually white or see through. It is used for bottles for syrup and yogurt cups.
It emits carcinogenic STIREN. Usually it is used for coffee cups or fast food packaging.
7 PC (or no labeling)
This is the worst plastic for food products because it emits chemical BPA. Unfortunately it is used for bottles for infants, sports bottles and containers for food storage.
It seems that plastics 2, 4 and 5 or the ones with label HDP, HDPE and PP dont emit chemicals. Worst packaging has labels 1, 3, 6 or 7. In this bottles the water is under chemical and temperature activity and in a case of extra filling it is exposed to bacterial pollution.