Official health guidance calls for prompt action and attention to the underlying cause. Cleaning visible mould alone may not resolve leaks, cold surfaces or ineffective ventilation. Consider the occupants’ circumstances and any heightened risk.
When a report arrives
Ask where the mould is, when it appeared, whether it is spreading and whether there is an active leak. A photograph helps locate the problem but does not establish its cause or the health risk.
- Record the first report, including one given to an agent or contractor. Ask which rooms are affected and whether a bedroom, heating or washing facilities can still be used.
- Ask sensitively whether anyone needs an adjustment to the response because of age, disability or a health condition. Record the practical need, such as avoiding a mouldy bedroom, without demanding a medical history.
- Active flooding, unsafe electrics, a collapsing ceiling or severe breathing symptoms need an immediate emergency response. Arrange suitable professional help and agree how the occupants will remain safe while the cause is investigated.
Inspect the whole moisture problem
Treat the visit as an investigation. Cleaning a patch before checking the building can remove useful evidence and leave the source of moisture untouched.
- Photograph the location and extent before work. Check roofs, gutters, pipework, seals, external ground levels and adjacent rooms. Ask whether the patch follows rain, bathing, cooking or a plumbing leak.
- Check heating, extract ventilation, air paths and cold surfaces. An extractor that makes a noise may still have a blocked duct or discharge into a roof space. Ask the contractor to confirm that it works.
- Use moisture or humidity readings as part of an assessment, with the instrument, location and conditions recorded. One reading alone cannot prove rising damp, condensation or tenant fault. Use an independent competent surveyor if the diagnosis is uncertain.
Agree a repair and communication plan
Give the tenant a written account of what was found, what remains uncertain, the work proposed and the next appointment. Distinguish a temporary measure from the repair that removes the cause.
- Allocate one person to own the case. Ask contractors to address leaks, ventilation or insulation defects as appropriate, explain drying time and specify safe treatment of affected materials.
- Do not make action conditional on the tenant buying a dehumidifier or changing their routine. Explain useful ventilation and heating measures alongside action on the building and any affordability concerns.
- If rooms cannot be safely used, assess interim arrangements and possible alternative accommodation with the insurer, adviser and relevant council where needed. Explain costs and arrangements in writing; do not promise insurance cover before it is confirmed.
Deadlines and closing the case
Scotland has specific damp and mould response duties from 6 October 2026. Use the Scottish deadlines guide alongside this investigation. Welsh fitness duties and existing English repair and fitness duties continue to apply; England's private-sector Awaab consultation is not an operative deadline.
- Schedule a follow-up after the repair and an appropriate drying period. Ask whether the patch, smell or symptoms have returned and inspect again if the answer is unclear.
- Compare photographs and findings with the original report. A completed invoice or freshly painted wall is not evidence that the moisture source has been resolved.
- Reopen recurrent cases with the previous diagnosis and works history. Escalate to a competent specialist when repeat cleaning, a disputed diagnosis or inaccessible building elements prevent a lasting solution.
Write an instruction the contractor can answer
A useful job instruction asks for findings and a proposed remedy, rather than simply asking someone to remove mould.
- Describe each affected surface and attach the first and most recent photographs. Ask the contractor to distinguish observed defects, possible causes and checks they could not complete.
- Request photographs of hidden defects before they are covered, the ventilation test or inspection findings, the work required and any further specialist assessment. Ask what must happen before decoration and when the outcome should be checked.
- Retain one case history when contractors or agents change. The Housing Ombudsman's reports provide useful service lessons from housing complaints; their recommendations should not be presented as additional statutory deadlines for every private landlord.
Example: mould returns after repainting
A fictional tenant reports mould behind a bedroom wardrobe. The first contractor washes and paints the wall, but the patch returns. The next instruction should ask for the moisture source and ventilation performance to be investigated, with dated findings and a repair proposal. Record the recurrence against the original case rather than treating it as an unrelated new report. Agree interim use of the room and a follow-up visit.
What to do
- Record the report, affected rooms and immediate concerns.
- Arrange a suitable investigation and an interim response where needed.
- Check the outcome after repairs and tell the occupant how to report recurrence.
Evidence to keep
- Report, photographs and investigation
- Work completed and follow-up findings
Sources and guidance
- Damp and mould: health risks and landlord actionUK Government · checked 20 October 2026
- Awaab’s Law: scope and requirementsScottish Government · checked 20 October 2026
- Fitness of homes for human habitation: landlord guidanceWelsh Government · checked 20 October 2026
- Damp and mould: learning from housing complaintsHousing Ombudsman: service learning, not a universal private-landlord duty · checked 20 October 2026
- Knowledge and information management: lessons for landlordsHousing Ombudsman: service learning · checked 20 October 2026