HHSRS: the hazards, how councils score them, and what a Category 1 hazard means

In England, HHSRS is changing from the old 29-hazard model to 21 hazards from 23 June 2026, while Wales stays on the 29-hazard list. Scotland and Northern Ireland do not use HHSRS: Scotland uses the repairing standard, and Northern Ireland retains its fitness standard.

What are the 29 HHSRS hazards?

England cut the HHSRS hazards from 29 to 21 by amalgamation from 23 June 2026, so the old HHSRS 29 hazards list is now current for Wales but not for new English HHSRS assessments. The 29 Welsh / historic HHSRS hazards are: damp and mould growth; excess cold; excess heat; asbestos and manufactured mineral fibres; biocides; carbon monoxide and fuel combustion products; lead; radiation; uncombusted fuel gas; volatile organic compounds; crowding and space; entry by intruders; lighting; noise; domestic hygiene, pests and refuse; food safety; personal hygiene, sanitation and drainage; water supply; falls associated with baths; falling on level surfaces; falling on stairs; falling between levels; electrical hazards; fire; flames and hot surfaces; collision and entrapment; explosions; position and operability of amenities; and structural collapse. The 2006 guidance said, “There are 29 hazards,” but England’s current landlord-and-agent guide now says, “The number of hazards has been reduced from 29 to 21, with several hazards amalgamated to simplify the assessment process.” GOV.UK’s general landlord responsibilities page still says, “Inspectors look at 29 health and safety areas,” but that page is stale for England.

What makes a hazard Category 1 rather than Category 2?

A hazard is Category 1 if its HHSRS score is 1,000 or more; below 1,000 it is Category 2, and England’s 2026 reform renamed the top scoring band “High” rather than changing the threshold. The Housing Act definition says a “category 1 hazard” is one that reaches “a numerical score of or above a prescribed amount,” and the 2026 English operating guidance states, “hazards scoring under 1000 are classified as Category 2 hazards, those scoring 1000 or over are Category 1 hazards.” The two key factors considered when assessing a hazard under HHSRS are the likelihood of a harmful event and the probable severity of harm; that scoring produces the band. In Wales, Category 1 remains bands A, B or C, with band C beginning at “1000 to 1999.” The practical enforcement difference is sharp: for Category 1, the authority “must take the appropriate enforcement action”; for Category 2, it has a power rather than a duty.

Is HHSRS a legal requirement?

HHSRS is a legal requirement for English and Welsh councils when enforcing housing conditions, but a private landlord does not have to commission a scored HHSRS assessment simply to let a property. The Housing Act 2004 describes Part 1 as the system “to be used in the enforcement of housing standards,” and MHCLG’s landlord guide says, “There is no requirement for landlords and property agents to become trained HHSRS assessors, but landlords need to keep their homes free of Category 1 hazards.” For fitness-for-human-habitation claims in England, GOV.UK is explicit that “A Housing Health and Safety Rating System (HHSRS) assessment is not necessary.” The legal duty is therefore not to produce an HHSRS certificate; it is to avoid conditions serious enough to trigger housing enforcement or unfitness. Scotland does not have HHSRS and uses the repairing standard. Northern Ireland has not adopted HHSRS and says its “current fitness standard will continue to be used.”

Who can carry out an HHSRS assessment?

A statutory HHSRS assessment is carried out by a local housing authority inspector, and English guidance says full scored assessments should be done by people trained in the HHSRS process, but the legislation does not create a closed licence or protected profession. The England Regulations define an inspector as “a person carrying out an inspection under section 4 of the Act,” and Wales uses the same definition. In practice, councils use “environmental health officers (EHOs) or other appropriately trained officers,” so the answer to who can do a HHSRS assessment is not EHO-only. England’s 2026 operating guidance draws the practical line: “Full assessments involving scoring should only be carried out by those trained in the HHSRS assessment process,” while preliminary safety checks can use the baseline indicators checklist. Private HHSRS-style reports exist, but they do not replace the council’s enforcement judgment. Abodient can hold inspection reports and compliance documents against the property, which matters because HHSRS disputes often turn on what was reported, when, and by whom.

Is mould a Category 1 hazard?

Mould is not automatically a Category 1 hazard: damp and mould is a prescribed HHSRS hazard, but it becomes Category 1 only if the scored risk reaches 1,000 or more. The England hazard description includes “Exposure to house dust mites, damp, mould or fungal growths,” but the category depends on the HHSRS scoring outcome, not on the mere presence of visible mould. From 23 June 2026, England’s Regulations say, “A hazard will be a category 1 hazard if its numerical score corresponds to the High band,” while Wales still says “a hazard falling within band A, B or C of Table 3 is a category 1 hazard.” The English Housing Survey shows why the distinction matters: “The most common Category 1 hazards found across all dwellings were falls on stairs (3%), excess cold (2%), falls on the level (1%), falls between levels (1%) and damp (1%).” So severe mould can be Category 1, but ordinary evidence of damp is not the same as a Category 1 finding.

Is an improvement notice an enforcement notice?

An improvement notice is one kind of Housing Act 2004 enforcement action, but its statutory name is “improvement notice,” not “enforcement notice.” Section 5 lists “serving an improvement notice under section 11” as appropriate enforcement action for a Category 1 hazard, and section 11 defines the document as “a notice requiring the person on whom it is served to take such remedial action in respect of the hazard concerned as is specified in the notice.” MHCLG’s landlord guide sometimes uses looser language, saying, “When an enforcement notice is served, the local council can charge a fee,” but that is an informal description of enforcement paperwork rather than a second legal instrument. For a landlord, the distinction matters because appeals, offences, works and deadlines attach to the actual statutory notice served. In Northern Ireland, the equivalent language is different again: a council may serve a “notice of unfitness,” not a Housing Act 2004 improvement notice.

When can a council prohibit a property from being used?

In England and Wales, a council can prohibit use of a property where it has a Housing Act 2004 power or duty to act on a Category 1 or Category 2 hazard and chooses a prohibition order rather than improvement works. A prohibition order is “an order imposing such prohibition or prohibitions on the use of any premises,” and it can restrict all use or a particular use of the whole premises or part of them. For Category 1 hazards, the council “must take the appropriate enforcement action”; for Category 2 hazards, it has a discretionary power. The difference between a prohibition order and an emergency prohibition order is timing and urgency: the ordinary order normally becomes operative after 28 days, while an emergency prohibition order imposes prohibitions “with immediate effect” where the statutory emergency conditions are met. England’s 2026 guidance says prohibition is more likely where remedial works are “unreasonable, inappropriate, or impractical,” or where improvement cannot mitigate the hazard, such as over-occupation causing crowding and space risk.

Last reviewed September 2026.

Sources

• Housing Health and Safety Rating System Operating Guidance 2006 — “There are 29 hazards.” Source
• Housing Health and Safety Rating System Regulations 2005, Schedule 1 — “29. The collapse of the whole or part of the dwelling or HMO.” Source
• Housing Health and Safety Rating System (Wales) Regulations 2006, Schedule 1 — “1. Exposure to house dust mites, damp, mould or fungal growths.” Source
• GOV.UK, Landlord and agent guide to the Housing Health and Safety Rating System — “The number of hazards has been reduced from 29 to 21, with several hazards amalgamated to simplify the assessment process.” Source
• GOV.UK, HHSRS Operating Guidance — “It is risk-based, set out in regulation and covers a range of 21 potential hazards.” Source
• GOV.UK, Renting out a property: landlord responsibilities — “Inspectors look at 29 health and safety areas and score each hazard they find as category 1 or 2, according to its seriousness.” Source
• Housing Act 2004, section 2 — “‘category 1 hazard’ means a hazard of a prescribed description which falls within a prescribed band as a result of achieving, under a prescribed method for calculating the seriousness of hazards of that description, a numerical score of or above a prescribed amount;” Source
• HHSRS Operating Guidance Part 1 — “Regulations made under the Housing Act 2004 state that hazards scoring under 1000 are classified as Category 2 hazards, those scoring 1000 or over are Category 1 hazards.” Source
• Housing Health and Safety Rating System (Wales) Regulations 2006, regulation 7 — “C 1000 to 1999” Source
• Housing Act 2004, section 5 — “If a local housing authority consider that a category 1 hazard exists on any residential premises, they must take the appropriate enforcement action in relation to the hazard.” Source
• Housing Act 2004, section 7 — “The provisions mentioned in subsection (2) confer power on a local housing authority to take particular kinds of enforcement action in cases where they consider that a category 2 hazard exists on residential premises.” Source
• Housing Act 2004, section 1 — “for that system to be used in the enforcement of housing standards in relation to such premises.” Source
• GOV.UK, Landlord and agent guide to HHSRS — “There is no requirement for landlords and property agents to become trained HHSRS assessors, but landlords need to keep their homes free of Category 1 hazards, which will require a degree of familiarity with the HHSRS and what a Category 1 hazard looks like.” Source
• GOV.UK, Homes (Fitness for Human Habitation) Act 2018: guide for landlords — “A Housing Health and Safety Rating System (HHSRS) assessment is not necessary.” Source
• Housing (Scotland) Act 2006, section 13 — “(a)the house is wind and water tight and in all other respects reasonably fit for human habitation,” Source
• Northern Ireland Department for Communities, Decent Homes Standard — “The current fitness standard will continue to be used as the minimum benchmark for housing in Northern Ireland; however this may be reviewed under future legislation.” Source
• Housing Health and Safety Rating System Regulations 2005, regulation 2 — “‘inspector’ means a person carrying out an inspection under section 4 of the Act (inspections by local housing authorities to see whether a category 1 or 2 hazard exists);” Source
• Housing Health and Safety Rating System (Wales) Regulations 2006, regulation 2 — “‘inspector’ (‘arolygydd’) means a person carrying out an inspection under section 4 of the Act (inspections by local housing authorities to see whether a category 1 or 2 hazard exists);” Source
• HHSRS Operating Guidance Part 1 — “Full assessments involving scoring should only be carried out by those trained in the HHSRS assessment process, however, preliminary property safety assessments can be completed using the HHSRS baseline indicators checklist (provided in Part 2 of this guidance).” Source
• GOV.UK, Landlord and agent guide to HHSRS — “They will employ environmental health officers (EHOs) or other appropriately trained officers to do this.” Source
• Housing Health and Safety Rating System Regulations 2005, Schedule 1 — “Exposure to house dust mites, damp, mould or fungal growths.” Source
• Housing Health and Safety Rating System (England) Regulations 2026 — “A hazard will be a category 1 hazard if its numerical score corresponds to the High band and a category 2 hazard if its numerical score corresponds to the Medium or Low band.” Source
• Housing Health and Safety Rating System (Wales) Regulations 2006, regulation 8 — “a hazard falling within band A, B or C of Table 3 is a category 1 hazard;” Source
• English Housing Survey 2023 to 2024, housing quality chapter — “The most common Category 1 hazards found across all dwellings were falls on stairs (3%), excess cold (2%), falls on the level (1%), falls between levels (1%) and damp (1%), Annex Table 1.8.” Source
• Housing Act 2004, section 5 — “(a)serving an improvement notice under section 11;” Source
• Housing Act 2004, section 11 — “An improvement notice under this section is a notice requiring the person on whom it is served to take such remedial action in respect of the hazard concerned as is specified in the notice in accordance with subsections (3) to (5) and section 13.” Source
• GOV.UK, Landlord and agent guide to HHSRS — “When an enforcement notice is served, the local council can charge a fee to recover costs reasonably incurred in taking enforcement action.” Source
• The Private Tenancies (Northern Ireland) Order 2006, Article 18 — “it may, subject to the provisions of this Part, serve a notice of unfitness under this paragraph on the owner of the dwelling-house.” Source
• Housing Act 2004, section 20 — “A prohibition order under this section is an order imposing such prohibition or prohibitions on the use of any premises as is or are specified in the order in accordance with subsections (3) and (4) and section 22.” Source
• Housing Act 2004, section 24 — “The general rule is that a prohibition order becomes operative at the end of the period of 28 days beginning with the date specified in the notice as the date on which it is made.” Source
• Housing Act 2004, section 43 — “An emergency prohibition order under this section is an order imposing, with immediate effect, such prohibition or prohibitions on the use of any premises as are specified in the order in accordance with subsection (3) and section 44.” Source
• HHSRS Enforcement Guidance 2026 — “Where it is possible to mitigate a hazard through works, this action is likely to be an improvement notice; however, it is more likely to be a prohibition order where remedial works are considered unreasonable, inappropriate, or impractical, or where it is not possible to mitigate a hazard by improvement works (e.g. over-occupation causing a crowding and space hazard).” Source