HHSRS Category 1 vs Category 2 Hazards: A Complete Guide

The Housing Health and Safety Rating System (HHSRS) is the primary method for assessing housing conditions in England. Under this framework, hazards are classified into two categories based on their severity—and this classification directly impacts your legal obligations, especially under Awaab's Law.

Getting this classification wrong can mean missed deadlines, regulatory action, and increased liability. This guide explains exactly how the system works.

What is HHSRS?

HHSRS is a risk-based evaluation tool introduced under the Housing Act 2004. It assesses 29 potential hazards across four main areas: physiological requirements, psychological requirements, protection against infection, and protection against accidents.

For each hazard, assessors calculate a numerical score based on:

• The likelihood of an occurrence that could cause harm
• The range of probable health outcomes (from mild harm to death)
• The vulnerability of the occupants (age, health conditions)

This score determines whether a hazard is Category 1 or Category 2.

Category 1 Hazards: The Most Serious

A Category 1 hazard is one where the HHSRS score reaches or exceeds 1,000 points. These represent serious and immediate risks to health and safety.

What Makes a Hazard Category 1?

• High likelihood of harm: The hazard is likely to cause an incident
• Severe outcomes: Potential for serious injury, chronic illness, or death
• Vulnerable occupants: Children, elderly, or those with health conditions at greater risk
• Widespread impact: Affects main living areas or multiple rooms

Examples of Category 1 Damp and Mould

• Extensive black mould covering walls in bedrooms or living rooms
• Mould in a property occupied by someone with asthma or respiratory conditions
• Severe condensation causing persistent dampness throughout the property
• Penetrating damp causing structural deterioration
• Any damp/mould affecting a child's bedroom

Category 2 Hazards: Significant but Less Severe

Category 2 hazards score below 1,000 points. They still pose a risk to health, but the likelihood or severity is lower than Category 1.

What Makes a Hazard Category 2?

• Moderate likelihood: Risk exists but occurrence is less certain
• Less severe outcomes: Likely to cause discomfort or minor health issues
• Limited scope: Affects smaller areas or less critical rooms
• Lower vulnerability: Occupants not in high-risk groups

Examples of Category 2 Damp and Mould

• Localised mould in bathroom corners with adequate ventilation
• Minor condensation on windows in winter
• Small patches of mould in utility areas
• Early-stage damp that hasn't yet caused mould growth

The Grey Area: When Classification Isn't Clear

In practice, many cases fall into a grey area. A moderate patch of mould might be Category 2 in one property but Category 1 in another, depending on:

• Who lives there (a healthy adult vs. an asthmatic child)
• Where the mould is located (utility room vs. bedroom)
• How long it's been present
• Whether conditions are worsening

This is why proper assessment and documentation is critical. You need evidence to support your classification—and to defend it if challenged.

Awaab's Law Timescales by Category

Why Accurate Classification Matters

1. Legal Compliance

Misclassifying a Category 1 hazard as Category 2 means you're working to the wrong deadline. If you take 14 days to start repairs on what should have been a 7-day response, you're in breach of Awaab's Law.

2. Regulatory Risk

The Regulator of Social Housing and Housing Ombudsman review how providers assess and respond to hazards. Systematic under-classification suggests a culture of minimising problems.

3. Disrepair Claims

In litigation, claimant solicitors will scrutinise your HHSRS assessments. If you classified something as Category 2 that clearly met Category 1 criteria, it undermines your defence.

4. Tenant Safety

Ultimately, the classification system exists to protect residents. Under-classifying hazards means vulnerable people live in unsafe conditions longer than necessary.

Best Practice: When in Doubt, Escalate

If a hazard could reasonably be classified either way, treat it as the more serious category. The consequences of over-classifying are minimal—you respond faster than strictly required. The consequences of under-classifying can be severe.

Document Your Reasoning

Whatever classification you apply, record why:

• Photographic evidence: Extent and location of the hazard
• Environmental data: Humidity, temperature readings
• Occupant information: Any vulnerability factors considered
• Assessment notes: Your reasoning for the classification

How Technology Supports Better Classification

Traditional HHSRS assessments rely on point-in-time inspections. The assessor sees conditions on one day and makes a judgment. But environmental conditions fluctuate—what looks moderate on a dry day might be severe during a damp spell.

Continuous monitoring provides objective data that supports more accurate classification:

• Humidity trends over time, not just a snapshot
• Temperature patterns that reveal heating adequacy
• Data showing whether conditions are stable or deteriorating
• Evidence that supports (or challenges) tenant reports