Damp and mould are present in thousands of homes across London and Hertfordshire. Recent surveys estimate 3.7% of London homes and about 17,855 homes in Hertfordshire have damp or mould problems. Complaints are concentrated in several London boroughs (Haringey, Hammersmith & Fulham, Lambeth, Lewisham among them), and council inspections and treatment orders in Hertfordshire show rising action to address the issue. If you smell mustiness, see black mould, or have condensation that won’t go away, arrange a professional damp survey — early treatment prevents health harm and expensive structural damage. (London City Hall)
Why this matters now
Damp and mould are more than an aesthetic nuisance — they damage buildings, reduce property value and can make people unwell. National surveys show large numbers of households affected (over a million households across England), and local reporting highlights clear hotspots in London and pockets of concentrated need in Hertfordshire. This post summarises the best public data, groups London boroughs so you can see local risk patterns, lays out the Hertfordshire picture, and gives clear, practical steps for homeowners, tenants and landlords. (GOV.UK)
Damp & Mould Statistics for London (2025)
📌 Key Findings
- 3.7% of London homes have damp or mould issues (London City Hall)
(London Assembly Research Unit, 2024) - 9.9% of London homes fail the national “Decent Homes Standard”
- Complaint-rate data shows that 8 of the worst 10 UK authorities for damp complaints are in London
- Social housing and private rentals are at highest risk due to overcrowding, poor ventilation and energy inefficiency
- National EHS data shows higher prevalence in rented tenures. (GOV.UK)
London Boroughs with Highest Damp & Mould Complaint-rates league table
These groupings reflect complaint rates and reporting patterns from the Regulator of Social Housing and press analyses. (The Standard)
Because official surveys usually don’t break down by borough, many recent “by borough” stats come from complaint data (e.g. reports from tenants, FOI requests, social-housing regulator data). This isn’t perfect (it reflects complaints, not all cases), but gives a relative ranking. For 2023/24 complaints:
| London Borough | Complaints about damp & mould (per 10,000 units) |
|---|---|
| Haringey | 30.71 |
| Hammersmith and Fulham | 29.07 |
| Lambeth | 26.83 |
| Lewisham | 25.86 |
| Camden | 16.96 |
| Islington | 16.09 |
| Southwark | 16.01 |
Why some boroughs show up worse
Complaint-based data is a useful indicator of pressure points (it’s based on reports to regulators or councils) but it measures reported problems rather than true prevalence across every home. Higher complaint rates may reflect more council-managed housing or greater tenant reporting. Use complaint rankings as a guide to hotspots, not a census of all cases. (The Standard)
Outer London boroughs
- Many outer boroughs show lower complaint rates in published rankings, but that is partly due to different housing mixes (more owner-occupied houses, fewer council flats). That doesn’t mean the problem isn’t present — it may be under-reported.
See how one IoT company is using sensors to help tackle damp and mould in council properties:
What this means for London homeowners, tenants and landlords
- If you live in an inner London borough, particularly the ones listed above, be proactive: inspect for mould, check ventilation and, if renting, report problems quickly (document via email).
- Landlords: councils often take enforcement action — keep records of repairs, and resolve moisture issues with a qualified damp specialist. Local authority enforcement is patchy but active in areas with many complaints; councils inspect many reported cases and can issue improvement notices. (The Guardian)
Damp & Mould Statistics For Hertfordshire (2025)
Although Hertfordshire does not publish borough-wide statistics in the same format as London, several public reports and council documents reveal the scale.
📌 Key Hertfordshire Data
- 17,855 homes affected by damp or mould county-wide
- 1,033 households with children under 14 living with damp or mould
- Stevenage Borough Council: damp/mould treatment orders increased from 301 to 519 homes in a year
- Dacorum Borough Council: multiple complaints logged in the social-housing sector
Those figures were used in local health planning to justify targeted prevention and Healthy Homes work. (Open Council Network)
These Hertfordshire damp statistics do reveal the scale, that’s no doubt.
What local councils are doing (examples)
- Stevenage Borough Council — inspections and treatment orders show rising numbers of council properties receiving damp/mould treatments (e.g., treated/inspected properties rising from 301 to 519 in a year in reported council stock). This indicates active remediation in social housing but also highlights prevalence. (Open Council Network)
- Dacorum and other districts have reported repeated resident complaints about leaks and damp in council housing — these cases show the human cost (health and wellbeing) and the need for timely repairs. (Hemel Today)
How Hertfordshire differs from London
- Hertfordshire figures are county-level estimates, and local responses (Healthy Homes programmes, public-health interventions) are the primary actions taken. London’s data often focuses on complaint-rates per 10,000 units; Hertfordshire’s emphasis is on counts of homes in need and targeted programmes for families and children. (Open Council Network)
Practical, step-by-step advice — what to do if you suspect damp or mould
1) Quick home checks (do them now)
- Look for black/grey mould around windows, behind beds, inside wardrobes, corners and skirting boards.
- Smell for musty odours (often an early sign).
- Check for flaking paint, peeling wallpaper, salt deposits on walls, or damp patches after rain.
- Test condensation: persistent window condensation after mornings is a red flag.
2) Short-term mitigation (keep everyone safe while you act)
- Improve ventilation: use extractor fans in kitchens and bathrooms, open trickle vents or a window for a short period daily.
- Reduce drying indoors (or use a vented dryer outside), keep lids on pots while cooking, and avoid long showers without ventilation.
- Move furniture slightly away from external walls to allow air circulation and prevent mould behind wardrobes.
3) Book a professional damp survey
- If you see sustained mould, stains, bulging plaster or water ingress: arrange a full damp survey. A proper survey will:
• Identify type(s) of damp — rising damp, penetrating damp, condensation.
• Use moisture meters and wall probes.
• Check ventilation, heating patterns and structural issues.
• Produce a written report with recommended remedial actions and estimated costs.
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4) Typical outcomes and why early action matters
- Minor condensation mould may be resolved with ventilation improvements and anti-mould cleaning; structural penetrating damp often requires repairs (roof, pointing, gutters or external waterproofing) and specialist drying. Social housing often requires both remediation and ongoing monitoring. Early action prevents expensive structural repairs and health consequences. (GOV.UK)
Prevention checklist (practical & easy to implement)
- Fit trickle vents or use extractor fans in wet rooms.
- Avoid drying multiple loads of laundry indoors in winter.
- Keep a low but steady heating profile in cold months to avoid cold surfaces where condensation forms.
- Insulate cold walls and lofts where feasible (EPC improvements reduce condensation risk).
- Regularly inspect roofs, gutters and external brickwork for leaks.
Actionable next steps & why you should act now
Damp and mould are widespread but treatable. London shows hotspots by borough (especially inner London areas with high complaint rates), and Hertfordshire’s county figures show thousands of homes and families affected. If you find early signs — acting now with simple ventilation changes and arranging a damp survey will save money and reduce health risks.
Next steps:
- Do the quick home checks listed above.
- Book a damp survey with Damp and Mould Solutions Ltd.
Landlords: keep written records of inspections & repairs — councils use complaint records when deciding enforcement action.
Why Damp & Mould Are Increasing
According to the English Housing Survey (EHS) and local authority health reports, damp and mould increases are linked to:
- Rising energy costs → reduced heating
- Old brickwork with no cavity barriers
- Poor ventilation habits during winter
- Condensation accumulating due to airtight windows
- Leaks, roofing deterioration, or failed damp proof courses
- Overcrowding in rental homes
External research confirms these trends:
- GOV.UK English Housing Survey
- London Assembly Housing Stock Report
- Hertfordshire Health & Wellbeing Board Papers
- Social Housing Ombudsman Annual Data Reports
How to Identify Damp & Mould in Your Home
You may have a damp issue if you notice:
- Black mould patches on walls
- Damp smells in bedrooms or wardrobes
- Flaking paint or bubbling plaster
- Cold walls or high moisture readings
- Condensation on windows in the morning
- Rotting skirting boards or floorboards
Health Impact: Why You Shouldn’t Ignore Damp or Mould
Damp and mould exposure can lead to:
- Persistent coughing or wheezing
- Asthma flare-ups
- Skin irritation
- Recurrent chest infections
- Fatigue, headaches, and poor sleep
- Increased hospital admissions in children
This is widely recognised by:
- NHS England
- UKHSA (UK Health Security Agency)
- World Health Organisation (WHO)
FAQ
How common is damp in London?
About 3.7% of London homes were recorded as having damp or mould in the most recent London housing stock report. This is lower than the England headline in some metrics, but several London boroughs have high complaint rates.
Which London boroughs have the most complaints?
Published complaint-rankings place Haringey, Hammersmith & Fulham, Lambeth and Lewisham among the highest for damp/mould complaints (complaints per 10,000 units). Use complaint data for hotspot targeting but pair it with local inspections.
How many homes in Hertfordshire have damp or mould?
Hertfordshire county papers estimate around 17,855 homes affected, with at least 1,033 households with children under 14. Local Healthy Homes initiatives are using these figures to prioritise interventions.
Is damp a health risk?
Yes. National surveys find large overlaps between damp homes and occupants with health issues; public health bodies consider long-term exposure to damp and mould an avoidable health burden. (GOV.UK)
When should I get a professional survey vs DIY?
If mould recurs after cleaning, you have visible structural damp, multiple rooms affected, or health symptoms (e.g., asthma worsening), book a professional damp survey. DIY fixes are OK for small condensation patches but not for penetration or rising damp.
Ready to act?
At Damp and Mould Solutions Ltd, we offer:
- Professional damp surveys
- Mould removal & decontamination
- Rising damp treatments
- Cavity wall and damp proofing solutions
- Ventilation and air-quality upgrades
- Long-term prevention strategies
- 📞 Book Your Damp Survey Today – Early intervention saves money and protects your health.