## Plastic bottles Water bottles are usually made from plastic-based polyethylene terephthalate. At the bottom of these bottles, you can find a PET or PETE symbol. However, plastic bottles are not optimal to drink from. One reason for this is that bacteria ===can get into a bottle after it is opened for the first time and grow in number. Second, if plastic bottles are improperly stored (for example, exposed to sunlight), the plastic starts to release toxic substances into the water. The longer you use the bottle, the higher the risks. You should never pour hot or warm drinks into water bottles, as this leads to the release of toxic substances. Additionally, PET bottles let UV rays in and are not oxygen-tight, which has an impact on the quality of water over time. ## Not all plastic bottles are the same Reusable water bottles are made from different types of plastic. These will have HDPE, LDPE, or PP symbols on the bottom. If you have one of these bottles, wash it in lukewarm (but not hot) water with soap or diluted vinegar. The highest concentration of the bacteria is near the top of the bottle, so you make sure to wash this area. If you see any micro-cracks on the surface of the bottle, you should replace them. ## The most ecological option Glass bottles are the most ecological and safest ways to store water. It doesn't produce a chemical reaction with water, even when heated, and doesn't let any dangerous substances get into the water. The downside to glass bottles is that they are heavy, fragile, and more expensive than plastic bottles. ## What to consider when buying bottled water __Smell:__ quality plastic shouldn't produce any smell. Therefore, if you can smell anything from a disposable or reusable bottle, you should look for another one. If there is a musty smell when you open the bottle of water, the water is probably not good to drink. __Date of production:__ the longer the water was stored, the higher the chances that its storage conditions were not ideal — which could let toxic substances into the water.