The Housing Health and Safety Rating System (HHSRS) is a new risk assessment tool used to assess potential risks to the health and safety of occupants in residential properties in England and Wales.   The legislation came into effect in England on 6 April 2006 and replaces the Housing Fitness Standard*

The HHSRS focuses on the hazards that are present in housing through a process of logical evaluation of the likelihood of an occurrence that could cause harm, and the probable severity of the outcomes from such an occurrence.   It is evidence based and is supported by extensive reviews of the literature and by detailed analyses of statistical data on the impact of housing conditions on health.   By focusing on potential hazards, more emphasis is directed at the risks to health and safety than was previously the case.

The HHSRS Formula

Three sets of figures are used to generate a hazard score:

a)   A weighting for each class of harm, reflecting the degree of incapacity that is likely to result from the occurrence.

b)   The likelihood of an occurrence involving a member of a vulnerable age group, expressed as a ratio: and

c)   The spread of possible harms resulting from an occurrence, expressed by percentage for each of the four classes of harm.

The first of these, the weighting given to each class of harm is fixed as shown in Table 1 below.   The weightings are designed to rank hazards so that those that can result in death, for instance, produce a higher score than less severe hazards.

Table 1 - Weightings for the Classes of Harm

Class of Harm                      Weighting

I    Extreme                        10,000
II   Severe                          1,000
III  Serious                          300
IV  Moderate                       10

The other two sets of figures represent the professional judgements of the informed professional officer of the likelihood and potential spread of harms.   The score is calculated as the sum of the products of the weightings for each class of harm, multiplied by the likelihood of an occurrence, and multiplied by the percentages showing the spread of harms as shown in Table 2.

Table 2 - The HHSRS Calculation

Class Of Harm Weighting         Likelihood         Spread of Harm (%)
I   10,000                          x       1/L           x          01                   = S1
II  1,000                            x       1/L           x          02                   = S2
III  300                              x       1/L           x          03                   = S3
IV  10                                x       1/L           x          04                   = S4

Hazard Score = S1 + S2 + S3 + S4

More detailed guidance can be viewed by following the link on the right side of the page.

*   Housing Act 1985, s 604, as amended by the Local Government and Housing Act 1989.