Hundreds of Woking Borough Council homes do not have vital fire safety checks or carbon monoxide alarms.
The Regulator of Social Housing found that more than 400 homes were “overdue high-risk remedial actions” from fire assessments, with about half classified as “very high priority”.
Work on these should have been completed within 24 hours of being discovered.
However, some cases are six months overdue.
For about a quarter of its houses, the council was also unable to confirm whether they had smoke detectors installed.
It was also unable to assure whether carbon monoxide detectors were installed in eight per cent of required properties.
The watchdog found the council had breached the Home Standard with the potential for “serious detriment” to tenants.
The council brought the management and maintenance of its social housing back in-house last year and referred itself to the regulators to “fully understand the issues with the standard” of its homes.
The council must regularly assess fire risks and take safety precautions. It has now started to rectify these failures.
Cllr Ann-Marie Barker, leader of the council, said: “Nothing is more important than the safety of our residents, yet this is a stark warning that the council has fallen short in its health and safety duty toward tenants.
“The council is implementing actions which will reassure tenants of our commitment to delivering safe homes for residents.”