The children and families minister has said he is shocked that some school pupils do not have access to free drinking water.
Nadhim Zahawi has urged heads to ensure children have access to free water and that free school meals pupils do not feel stigmatised in a letter sent to schools today.
Child hunger: One in nine pupils arrive at school hungry
He has also urged schools to consider whether they are doing all they can to provide a positive lunchtime experience.
His letter comes as Tes revealed that around 100,000 pupils are not claiming free school meals despite being eligible.
Mr Zahawi said he wanted to bring the inquiry's findings to schools' attention.
In his letter, he said: “I was shocked to hear some young people report that they do not have access to free drinking water at school and often have to buy a bottle of water.
“Schools are legally obliged to provide access at all times to free drinking water on the school premises.
"I would urge you to consider whether you need to do more to make free water as easily available and as visible as you can.
"I would also encourage the use of refillable bottles, alongside other steps to reduce single-use plastics.”
He also urged schools to do more to avoid any stigma being associated with free school meals.
He said: “No child should feel stigmatised because they are entitled to free school meals. I know that many schools use cashless systems and other methods to ensure that children who are eligible for free school meals are not identified separately.
"However, I would encourage you to consider whether there is more that can be done, including ensuring that there is no limit on the choice available to free school meal pupils.”
A recent report by the Social Mobility Commission identified perceived stigma and lack of awareness as being among the reasons why families do not claim free school meals.
The minister has also encouraged schools to ensure pupils have affordable healthy choices, avoid queues and have enough time and space to eat with their peers, in line with the Children's Future Food Inquiry findings.
The letter comes as new figures suggest one in nine children arrive at school hungry.
A poll of 4,000 pupils and almost 1,000 teachers revealed concerns that some pupils are losing six hours of learning a week because of hunger.