Powdered formula is not sterile; so, even though tins and packets of formula powder are sealed, they can sometimes contain harmful bacteria that could make your baby ill. Water that hasn't been boiled can also contain bacteria and as a baby's immune system is not as strong nor as well developed as an adult's this means that babies are much more susceptible to illness and infection. Therefore, good hygiene is very important when making up a feed.

In line with NHS guidelines, we recommend that you always use boiled water (that has been cooled down to at least 70 ºC) when preparing baby's formula. The boiling process kills harmful bacteria that may be in the water or in the baby formula powder. We recommend that you bring at least one litre of water to a rolling boil and then leave the water to cool, but for no more than 30 minutes so that it remains at a temperature of at least 70ºC.

Do not use repeatedly boiled water as the balance of minerals in previously boiled water may not be suitable for making up formula feeds.