Revealed: The UK’s Mouldiest Counties

Are you dealing with mould in your home? You’re not alone. Homeowners and renters alike are dealing with damp and mould up and down the country.

The UK’s wet, cool climate means that mould is a common problem, though it’s unclear how bad the extent of the issue actually is. According to one GOV.UK publication from August 2024, up to 6.5 million households in the UK could be dealing with damp and mould, with renters more likely to experience mould than owner-occupiers.

The recent release of the Mouldy Nation 2025 report indicated that Britain’s mould problem has consistently worsened since 2019, with year-on-year complaint increases of up to 17.7%. So, we caught up with the experts at UltraTile to shed further light on which of the UK’s counties have experienced the most mould complaints, with information obtained via Freedom of Information requests.

Revealing the UK’s major mould hotspots

So, which of the UK’s counties experienced the most complaints about mould?

Well, unsurprisingly, London led the way in terms of volume of complainants, with 1,032 complaints filed with the Housing Ombudsman last year combined across Inner London and Outer London. There was a sudden jump to the next-highest county – the West Midlands with 89.

To gain more insight into the volume of complaints per person, however, UltraTile have used population data from the most recent UK census (2021/22), revealing the areas with the highest volume of mould complaints per million people.

Adjusted for the area’s population, London still leads the way, which is likely due to the city’s population density. Interestingly, all other regions in the adjusted top five are in the South East or East of England – East Sussex, Hertfordshire, West Sussex and Hampshire, respectively.

The presence of mould in these areas might be down to these areas experiencing higher levels of rainfall and humidity than most of the UK, but the wider increase in the number of mould complaints nationwide suggests there are quality issues with the UK’s housing stock.

What does this mean for UK renters and homeowners?

Typically, the Housing Ombudsman is considered the next point of recourse after failing to find support from your landlord. So, mould complaints to the Ombudsman pose another question – do these mould hotspots also host some of Britain’s least-active landlords?

Josh Jinks, UltraTile Brand Manager, comments: “In many cases, mould can be tackled quickly and easily with timely intervention. However, when patches of damp and mould are left untreated, they can quickly spread and cause a far more significant problem.

“In my experience, most renting tenants are quick to spot the appearance (and smell) of damp and mould. In being forced to contact the Ombudsman, it’s likely that their landlord has failed to provide adequate help and support in tackling the mould properly.”

He continues: “It’s important to note that the list here is not exhaustive – if anything, people who have been forced to make a complaint to the Ombudsman are those who have been dealing with some really severe damp, so there could be millions of households living with damp that aren’t even covered.

“Part of the issue is likely down to poor housing stock – if insulation is lacking, windows are inefficient or damp and structural issues exist, then issues like damp are going to be more common than ever.”

So, if you find yourself dealing with mould in your home in one of the counties listed, don’t worry. You’re not alone, and most of the time, mould is easily tackled with the right resources. Always remember, if you feel your landlord is providing inadequate support for you, the Ombudsman might be able to help.