UK tap water tastes especially ‘musty’ this week — here’s why

Yesterday, parts of the UK saw rain for the first time in over 50 days, with Brits saying they’d ‘never been so happy’ to see a downpour.

With millions of residents in South and Central England still under a hosepipe ban, seeing the clouds turn grey and empty buckets onto the streets was a truly miraculous sight.

But while the heavy rainfall offered a welcome break from this summer’s relentless drought, some might notice a less-than-pleasant side effect.

According to experts, you may detect a ‘musty’ or ‘earthy’ undertone to your tap water over the next few weeks, all thanks to the changing forecast.

If you live in England, particularly in London, you’ll be all too familiar with the national gripe we have with our water.

In 2024, researchers at Imperial College London found trace amounts of what they described as ‘forever chemicals’ in our capital’s H2O. However, the levels detected were still within UK and EU safety limits.

But just because our tap water might meet regulatory standards, its reputation is abysmal, described as ‘undrinkable’ by some on social media.

‘Water down south is so gross’ @soph shared on TikTok, while @deebee added: ‘Water in the UK is surely not safe to drink’.

Why is my tap water tasting ‘musty’ right now?

If that was even possible, our water be tasting even worse right now— with Dr Bill Simpson, chartered chemist saying it’ll likely have a particularly ‘earthy’ or ‘musty’ tang.

The in-house taste expert at Our Taap tells Metro the wet weather we’ve had this week is likely to be to blame, explaining: ‘Heavy rainfall can create problems for those responsible for treating water and can even lead to the water from our taps taking on a variety of unpleasant notes.’

There are a number of different reasons why the flavour of our tap water can change following a downpour, particularly when heavy rain comes after a prolonged period of drought.

Because the ground has been so dry and hard, when it does eventually rain, water is less easily absorbed into the soil. Instead, more runs off the surface, carrying soil, pollutants and other materials into our natural water sources.

Dr Simpson says: ‘In the days that follow heavy rainfall, when the sun comes out again, the higher concentrations of phosphate and nitrate – which have been washed into waterways during heavy rain – allow photosynthetic bacteria and algae to grow.’

These extra nutrients can then encourage algae and bacteria to flourish, producing compounds that give the water that ‘earthy’ flavour and smell; compounds he claims are ‘notoriously difficult to remove during water treatment’.

‘In some cases, even after this “earthy” water is treated, it still can’t be supplied to consumers, and has to be blended with better sources of water, which are free of such compounds,’ Dr Simpson continues.

According to the expert, the more ‘stuff’ there is in our water after rainfall, the more work needs to be done to remove it before supplying it to consumers’ taps.

But water treatment stations have volume requirements to meet. So, ultimately a compromise has to be struck.

And since plants need to remove enough of the contaminants to make a difference and ensure our water is safe to drink, but aren’t required to make the water quality ‘pristine’, in some circumstances, traces of these taste and odour compounds may remain after treatment.

Despite this, Dr Simpson stresses that the water is still safe to drink, adding: ‘We’ve pretty much eliminated the chance of getting sick from drinking tap water in this country’.

Why does my tap water taste like chlorine?

It’s not just an ‘earthy’ taste. Some Brits might notice a ‘chlorine smell’ in their water too.

Dr Simpson explains that the cocktail of pollutants and microorganisms that run into our water sources ’cause a whole world of pain’ for the treatments plants who clean raw water from lakes, rivers, or wells so it’s safe to drink. 

He adds: ‘Higher chlorine levels may have to be used during treatment in an attempt to lower the levels of microorganisms in the water.

‘Chlorine is also added during the normal treatment process of our water to combat harmful microorganisms.

With this all in mind, he recommends anyone struggling with the taste consider treating their tap water at home a water softener system – a whole-house device that’ll help remove any hard minerals.

But if you don’t have the funds, a standalone tap water purifier, which uses activated carbon filters to improve taste and reduce chemicals, should help at least somewhat.

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