You do not like to drink tap water and prefer to buy bottled mineral water? So look closely at the triangle and the number printed in the middle. You will make many discoveries. You pay attention to the composition of the water but you do not pay attention to the chemical composition of the packaging. At the bottom of each package, look for the triangle with the number listed in the center and decipher the dangerousness of the plastic you hold in your hands.
1 – PET (often PETE)
These bottles, for the most part, are for single use only. It is possible that they emit antimony from heavy metals, an EPA chemical that interferes with the action of hormones. This substance may also be a carcinogen.
2 – HDPE (sometimes HDPE)
This means that this plastic has the lowest concentration of chemicals to diffuse into the water.
3 – PVC (parfois 3V)
4 – LDPE
Plastic that does not emit chemicals in the water. But that is used most often for the manufacture of plastic bags instead of bottles of water.
5 – PP
6 – PS
7 – PC (or no labeling)
This is the worst kind of plastic used for food packaging because it emits chemical BPA. Unfortunately, it is used for baby bottles, drinks bottles for sportsmen and for storing food.
It would seem that plastics 2, 4 and 5, ie those with HDP, HDPE and PP labels do not emit chemicals. The most dangerous are labels 1, 3, 6 or 7. In these bottles, the water is under chemical and thermal activity.
Source Here’s what the symbols on water bottles mean. :