The government should make councils provide public toilets and help fund them, says the British Toilet Association (BTA).
The advisory body says its figures show that the number of public loos has fallen by 40% in the past decade.
Director Raymond Martin said: "We know of a number of councils who have no public toilets whatsoever."
The government said councils were "flushing away" cash that could be spent on providing toilets.
The BTA, which has been holding its annual meeting in Stratford-upon-Avon, says the government should make toilet provision statutory and give councils funding.
'Health and wellbeing'
Mr Martin said: "Toilets are being closed in towns and cities across the UK. Councils have no financial or legal responsibility to provide toilets. It's a discretionary service and we want the government to change that.
"This is about people's health and wellbeing. The lack of public toilets affects a lot of people, including the elderly, pregnant women and children."
Local Government Minister Brandon Lewis said: "Public toilets are an important local service.
"If councils stopped flushing away taxpayers' money through bad procurement, bloated bureaucracy and fraud, they could find the savings to protect front-line services and keep council tax down."