What is an HHSRS damp and mould hazard?

An HHSRS damp and mould hazard is a risk identified through the Housing Health and Safety Rating System, the framework councils use to assess conditions in homes. It is more than a label for a patch of mould. An officer looks at the whole property, considers what is contributing to the problem, and assesses the risk before deciding what action is appropriate. A photograph alone cannot tell you which hazard category your home falls into.

What the assessment looks at

The HHSRS is a risk-based assessment of housing conditions. The current framework covers 21 potential hazards, with damp and mould growth among them. New regulations brought a review of the system into force in 2026, including an updated assessment and scoring process. If you have seen older descriptions of the system, their hazard lists may differ from the current guidance.

Damp and mould can have more than one contributing problem. The tenant guidance links it with a lack of heating and also identifies poor ventilation, leaks and gutters as possible contributors. That is why an assessment should look beyond the visible stain. It may involve the heating, the way rooms are ventilated and any water entering the building. A council officer may notice other concerns during an inspection, even if your complaint was only about one wall.

If a council decides to inspect, the officer considers the entire property. They may need access to all rooms and the garden; in a flat or shared house, communal areas may also matter. The officer can make notes, take photographs and ask questions. The information from that visit feeds into the HHSRS assessment. You do not need to work out a score yourself before reporting a problem.

What do the hazard categories mean?

The assessment gives each hazard a score and places it in a category. Category 1 is the most dangerous level; if a council finds a Category 1 hazard, it has a duty to take enforcement action. Category 2 covers hazards assessed below that level. A council has the power to take enforcement action for a Category 2 hazard, but the choice is at its discretion. Neither category tells you, by itself, which repair will solve the underlying damp.

The council chooses a course of action intended to remove the risk or reduce it to an acceptable level. Its decision is based on the assessment and the circumstances, rather than on the size or colour of a mould patch. A hazard awareness notice, for example, tells a landlord about a hazard and how to address it without requiring action. Other enforcement routes can require work. It is sensible to ask the council what it has found and what it expects to happen next, rather than assuming every complaint leads to the same response.

What should you do if you rent?

Tell your landlord or managing agent what you have found, preferably in writing. Describe where the damp or mould appears, whether water is getting in, and what happens with the heating or ventilation. Photos or video can help explain it. Keep copies of your messages and any response. This gives everyone a clear account of the concern and what has been done about it.

The tenant guidance says the landlord or agent should acknowledge the issue promptly and explain the action they will take. If the matter is not resolved to your satisfaction within a reasonable period, you can complain to your local council. Give the council enough detail to assess urgency and answer any questions it asks. A council might first handle a complaint by email or telephone; an immediate visit is not the only sign that it is considering the issue.

If you are a council tenant, raise the problem with the council as your landlord. The HHSRS assessment and the way a social landlord responds to a damp complaint are related but separate matters. Awaab's Law provides a route for social housing tenants dealing with damp and mould or emergency hazards; it is not the name for an HHSRS hazard category. The tenant guide says it will apply to the private rented sector in future, so do not assume that the same route already covers a private tenancy.

A cold rented terrace in Calderdale, Yorkshire

Imagine a rented terrace in Calderdale with mould on a bedroom wall, a cold room and a leak near a gutter. It would be easy to focus only on cleaning the mark. The guidance points towards a wider look: heating, ventilation, leaks and gutters may all be relevant to damp and mould. A council inspection would consider the entire home, not just the bedroom where the problem was first noticed.

For the person living there, the practical first step is to report each observed problem clearly, with photographs and a written record. For the landlord, it is to respond and investigate what needs attention. If the source of the damp is unclear, an independent, suitably qualified surveyor can help establish the cause before a repair is chosen. The council, if involved, makes its own assessment; nobody can assign the terrace a hazard category from this example.

Why the cause matters

A mould mark tells you where a problem is visible, but it does not settle why moisture is there. The HHSRS approach helps keep that distinction clear. A useful account of the home includes where the problem appears, when it changes, whether there are leaks, and how heating and ventilation work. That information can help a landlord investigate and help a council decide whether an inspection is needed. The lasting aim is to address the conditions behind the hazard, rather than guess from the appearance of one patch.

This page gives general information, not legal or medical advice. For your own situation, use the organisations listed under "Where this comes from" at the foot of the page.