The Natural Hydration Council endorses any initiative that encourages people to drink more water ('Top tips to help you economise', 20 January). However, it is important not to ignore good hygiene practices whilst doing so and we urge caution when considering re-filling bottles.
Bottled water is supplied in safe, sanitised bottles, which isn't the case when you refill it with another liquid. If bottles are not properly sterilised before re-use they can act as a breeding ground for micro-organisms.
Bottled water is one of the healthiest and most natural drinks you can consume and its naturalness is a reason why some choose it over treated water.
Consultant to NHC, London