The earliest evidence we have of people using glass to make containers for carrying liquids is clear water bottles from ancient Egypt (approximately 1500 B.C.). The clay pots that had been used previously were heavy and easily broken, and this was an easy way to transport water securely.
However, the question specifically asks when did water bottles start? Early records show that by 500 BC early Andean societies in Ecuador and Peru began reusing large ficus leaves as a disposable type of container for hydration, with these leaves being commonly known as “chichas”.