“Providing better school toilets as standard across Scotland is a matter of respect and dignity for children and young people,” said Tam Baillie.
He was speaking at the launch of a campaign demanding urgent action from the Scottish government.
Current legislation dates back to the mid-1960s and does not demand that school inspectors look at toilets, he explained.
“There is no process to ensure compliance with even basic standards and no-one systematically challenges the standards of school toilets when they do not come up to scratch.”
More than half – 56 per cent – of pupils never used school toilets or only used them if they “really had to”, according to a survey of more than 2,000 S1 to S6 children by Ipsos MORI in March this year.
Of those who did use school toilets, 16 per cent said they rarely or never felt safe in them, and 15 per cent said they only sometimes did.
“It’s an issue that particularly affects children and young people with health conditions or disabilities, who already face the highest barriers to inclusion in our society,” Mr Baillie said.
Adolescent girls and children who are being bullied are also affected disproportionately.
While lack of provisions or privacy often deters pupils from using the toilets, so does withholding of permission.
Among those who have to ask to go, only about a third say they are always or usually allowed,
16 per cent say they rarely are, and two per cent say their teachers never let them go to the toilet during class.
This can lead to chronic constipation, incontinence and urinary infections, or boys and girls may drink less during the day to avoid needing to go, causing dehydration.
The Commissioner is seeking not just an improvement in toilet facilities but also in the way they are monitored and guaranteed, so that this falls into line with workplace facilities for adults.
Eileen Prior, executive director of the Scottish Parent Teacher Council, welcomed the campaign, saying that parents were concerned about poor school toilets and the “frankly Dickensian attitudes that sometimes mean children are not allowed access to them”.
She encouraged parent councils to support the campaign and take up any concerns they have with their school, local authorities and MSPs.