Category 1 Hazard

The HHSRS is a risk-based system, set out in regulations under the Housing Act 2004, used to assess 21 potential categories of hazard in homes, from damp and mould to fire safety and overcrowding. An assessing officer scores each hazard according to the likelihood of harm and how serious that harm could be. A hazard scoring 1,000 or more is a Category 1 hazard — the 'high risk' tier — while anything scoring below 1,000 falls into Category 2, which is further split into 'moderate risk' and 'low risk'.

The distinction matters because it determines the council's legal duty. Local authorities must take enforcement action if they find a Category 1 hazard, whereas for a Category 2 hazard they only act if they consider it necessary to do so. Enforcement options range from a Hazard Awareness Notice through Improvement Notices and Prohibition Orders to the authority carrying out emergency remedial works itself — the two most urgent measures, an Emergency Prohibition Order and emergency remedial action, are available only where a Category 1 hazard poses an immediate risk of serious harm.