Wrexham and Denbighshire will be the latest authorities to withdraw the service after Powys, Monmouth and Newport stopped providing it in recent years.
Carmarthenshire was the first council to withdraw the service in 2011.
Nine local authorities now charge for dealing with all infestations, which is up from six councils two years ago.
Swansea, Bridgend, Caerphilly, Flintshire, Rhondda Cynon Taf, Ceredigion and Conwy deal with rats for free, but charge for other types of infestations.
Health professionals are now warning of potential risk to children and pets from accidental poisoning as people try to solve problems themselves, rather than call private pest control companies.
Julie Barratt, director of Chartered Institute of Environmental Health Wales, told Newyddion 9: "It's important to remember that council officers, pest control operatives were specialists.
"They knew what they were doing. They put pest products down in the right places, in safe places, they came along and checked them regularly and took them away.
"There is a real risk if people are left to their own devices that we're going to see cases of accidental poisoning of children and domestic pests and that's a real concern."
A Welsh Local Government Association spokesperson said: "Local councils in Wales face huge financial challenges, and this year alone will have to manage a collective £300m shortfall in their budget.
"With public sector austerity expected to last well into the future it is unavoidable that non-statutory services like pest control will continue to be placed under increasing financial pressure as councils try to balance the books."

He was admitted to hospital near Delhi last Friday in a critical condition after complaining of breathlessness.
A leading figure in the drive to build a temple at a disputed religious site in Ayodhya, he was known for his anti-Muslim remarks. Ayodhya has sparked deadly riots and remains a flashpoint.
Prime Minister Narendra Modi described his death as "a deep personal loss".
Mr Singhal was the international president of Vishwa Hindu Parishad (VHP) - an affiliate of the Rashtriya Swayamsevak Sangh (RSS) - for more than 20 years. The VHP is a close ally of Mr Modi's ruling Bharatiya Janata Party.
"He passed away at 2.30pm today. He had multi-organ dysfunction, ARDS [acute respiratory distress syndrome] and sepsis and was being treated by a team of specialists," The Times of India quoted Dr AK Dubey of Medanta hospital in Gurgaon as saying.
The 16th Century Babri Masjid (mosque) was torn down in 1992, allegedly by activists of VHP and other hardline Hindu groups who claim the site is the birthplace of their deity, Ram.
Tributes have been pouring in for the controversial leader on Twitter. In a series of tweets, Mr Modi described him as "an institution":
Soon after the news of his death became public, Ashok Singhal began trending in India and was also the number two trend worldwide. Many tweets praised his role in "resurrecting" Hinduism in India, but not everyone shared that opinion.
More than a quarter of Welsh councils will not provide pest control services to private homes from 1 April.
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Ashok Singhal, a senior leader of India's Hindu nationalist Vishwa Hindu Parishad movement, has died aged 89.