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Best Tap Water Quality in the UK – Study


Lee Devlin

Published on: 17/03/2021
Taps image

Whether you’re drinking, bathing or washing your clothes in it, the water quality and composition in the UK can differ greatly depending on where you live. But did you know it could impact you impact your washing, soap usage, and even skin?

We’ve analysed government-backed and water authority data to reveal the water quality in your area. Whilst also speaking to experts, to help inform you of the impact of high (and low) levels of lead, nitrates, aluminium, turbidity, and water hardness.

Ever wondered what’s in your water? This guide will help.


Key Findings From Our UK Water Quality Study

  • South London, East Surrey, and West Kent have the highest levels of lead in their tap water (2.60ug/l), 26% of legal limits
  • Hertfordshire (0.33 NTU) has the highest levels of turbidity in the UK, twice as high as the UK average (0.15 NTU)
  • Nine areas and counties in England have very hard water, potentially causing skin irritation and increased skincare costs
  • Luton, Thames Valley, North Wiltshire have the highest level of nitrates in water tests, 64.2% of legal limits
  • South London, and bordering East Surrey and West Kent, have the highest average rate of impurities against legal limits
  • Flintshire and Denbighshire have the lowest average rate of impurities in water quality tests

What’s In The Water Where You Are?

UK Water Quality Test Results Around England and Wales

Using the chart above you can see the water quality samples from over parts of England and Wales, from 19 different water authorities, showcasing the figures of the 5 (five) main elements and contaminants in UK water supplies. Those being:

  • Aluminium
  • Lead
  • Nitrates
  • Turbidity 
  • Water hardness

Highest And Lowest Readings

ElementHighest ReadingsLowest Readings
AluminiumDorset, Somerset, WiltshireHertfordshire, Berkshire
LeadEast Surrey, South London, West Kent Durham, Northumberland, Tyne and Wear, North Yorkshire
NitratesLuton, Thames Valley, North WiltshireCumbria, Greater Manchester, Lancashire, Merseyside
Turbidity HertfordshireLeicestershire, Staffordshire, Warwickshire, West Midlands
Water hardnessCambridgeshire, Lincolnshire, Northamptonshire, Nottinghamshire, Norfolk, Suffolk, Bedfordshire, Buckinghamshire, EssexPowys, Shropshire, Cornwall, Devon, Cumbria, Greater Manchester, Lancashire, Merseyside

Which Areas Of The UK Have The Highest Levels Of Lead In Their Water?

Rarely found in natural water sources, such as natural springs, lead is a dangerous metal that has been banned in plumbing in the UK for more than 25 years. However, if your house was built before 1970 there are (or were) most likely lead pipes somewhere in the water system of your home.

With this in mind, and despite various initiatives by the EU, UK government, and water authorities, many areas and homes across the UK still use or have concentrations of lead piping and connectors in their system; both in the mains and within people’s own houses.

Map Of Lead Readings Across England And Wales

Counties with the Highest Levels of Lead in Their Water - Homecure Plumbers

Areas with highest levels of lead: East Surrey, South London, West Kent 

Highest readings and percentage of legal limit: 2.60ug/l | 26%

Our research found South London, and the West Kent and East Surrey boarders to have the highest levels of lead in their water in the UK (2.60ug/l), followed by West Sussex (1.65ug/l), and much of the North West (1.29ug/l).

In terms of legal limits, all of the results analysed were below the 10ug/l limit imposed in the UK. However, with readings of 26% the legal limit, South London, East Surrey and West Kent have a 36.5% higher reading of lead than the second-highest, West Sussex (16.5% legal limit).

Meanwhile, our data found that Northumberland, Tyne and Wear, and Durham have the lowest levels of lead in England, with just 0.03 micrograms of lead per litre (ug/l), just 0.30% of the legal limit. 

Speaking to Brian Campbell, of, Brian shares: 

“The biggest issue with lead is that it’s an accumulative metal, which means that if you drink low levels of lead from childhood to old age, it will build up in your body throughout your lifetime. That’s what makes lead so dangerous – once it enters the body, it can’t be expelled.”

“Drinking lead in water may lead to cardiovascular issues and decreased kidney function, as well as reproductive problems. It’s particularly important to avoid this contaminant if you’re pregnant, as lead from water can pass through the blood into the foetus, resulting in delayed growth.”

“Overall, lead consumption is significantly more damaging in young children. Lead has been linked to poorly-functioning blood cells, impaired hearing, learning disabilities, and nervous system damage. Lead in water may also result in anaemia, lower IQ, and slowed growth in children.”

If you are concerned about whether you have lead pipes please view a guide to checking your pipes for lead.

Which Areas Have The Highest Levels Of Nitrates In Their Water?

A natural compound of nitrogen and oxygen, nitrates are often found in foodstuffs that make up a ‘normal’ diet.

Their presence resulting from natural and manufactured fertilisers, usually as part of intensive farming efforts, where they percolate into groundwater systems or ‘run off’ into rivers and other water sources that then enter our drinking water systems.

Map Of Nitrate Readings Across England And Wales

UK Counties with Nitrates in Their Water Quality - Homecure Plumbers

Areas with highest levels of nitrates: Luton, Thames Valley, North Wiltshire

Highest readings and percentage of legal limit: 32.10 mg/l | 64.20% 

Our research found Luton, Thames Valley and North Wiltshire have the highest levels of nitrates in their water quality tests, with readings 64.2% (32.10 mg/l) of UK legal limits (50 mg/l). Followed by South East Hampshire which had readings of 64% (32 mg/l) of legal limits, and Greater London (31.3 mg/l) with 62.6% of the UK limits.

At the other end of the scale, much of the North West, including Cumbria, Greater Manchester, Lancashire, and Merseyside, were found to have the lowest nitrate levels, at just 1.94 mg/l (3.88% legal limit).

Speaking of the risks of nitrates in tap water Brian Campbell shares:

“When children drink water containing nitrates, they’re at risk of “blue baby syndrome” (methemoglobinemia). This condition converts haemoglobin in infant blood cells to methemoglobin, which can’t carry oxygen, leading to nail beds, lips, nose and mouth to turn blue – hence the name “blue baby syndrome” – and may also be accompanied by vomiting, diarrhoea, and fever.”

“In Adult bodies, we have enzymes that protect them from haemoglobin conversion, but high levels of nitrates may still cause general health effects of drinking water containing nitrates, including headache, nausea, and gastrointestinal disorders.”

Which Areas Have The Highest Levels Of Aluminium In Their Water?

Aluminium is rarely found in natural water sources, instead of being added to our tap water in the form of salts during the cleaning and purification of our tap water, at water treatment centres and plants.

The salts added at treatment centres and plants aid in the removal of potentially harmful particulates, microbes and other microorganisms that can survive in water. Though not officially a harmful substance, aluminium can impact the colour and taste of tap water; leading to the UK government imposing a 200 micrograms per litre (ug/l) limit on aluminium traces.

Map Of Aluminium Readings Across England And Wales

Counties with the Highest Levels of Aluminium in Their Water Quality Tests - Homecure Plumbers

Areas with highest levels of aluminium: Dorset, Somerset, Wiltshire

Highest readings and percentage of legal limit: 63 ug/l | 31.5%

Dorset, Somerset and Wiltshire were found to have the highest levels of aluminium in water tests in 2020, with 63 micrograms of aluminium found per litre (31.5% of the UK legal limit).

Close behind the South West areas of the UK were Durham, Northumberland, Tyne and Wear, and parts of North Yorkshire, where aluminium results were found to be 28.5% the legal limit (57 ug/l).

Conversely, Hertfordshire and Berkshire had the lowest levels of aluminium found in their water, with just 5 ug/l (2.50% legal limit). 

Note: Current studies concerning the link of aluminium in water and Alzheimers are yet to be confirmed. For more information on the subject please visit.

Which Areas Have The Highest Levels Of Turbidity In Their Water?

Related to the clarity of a liquid, turbidity is the measure of the cloudiness and ‘opaqueness’ caused by particulates present in the water. These particulates can include (but aren’t limited to); silt, clay, microplastics and other non-organic materials, plankton, algae, and microscopic organisms.

As the list suggests, drinking water with high turbidity isn’t just aesthetically unappealing but can also have very real health concerns, as particulates can provide food and shelter for pathogens in the water, or be pathogens of themselves.

Map Of Turbidity Readings Across England And Wales

Counties with the Highest Levels of Turbidity in Their Water Quality - Homecure Plumbers

Areas with highest levels of turbidity: Hertfordshire

Highest readings and percentage of legal limit: 0.33 NTU | 8.25%

Hertfordshire was found to have the highest turbidity level in the results analysed, with a reading of 0.33 Nephelometric Turbidity Units (NTU); followed by Essex (0.25 NTU).

Legally in the UK, drinking and tap water must remain below four (4) Nephelometric Turbidity Units (NTU). However, the World Health Organisation (WHO) goes further, advising that levels should be below one (1) NTU.

The areas analysed with the lowest levels of turbidity were Staffordshire, Warwickshire, and the West Midlands, with levels of just 0.01 NTU. 

Speaking to Brian Campbell, Brian shares:

“The biggest problem with turbidity is that it offers the perfect environment for pathogens to grow, giving them shelter and food. Even low levels of turbidity, therefore, can encourage the production of pathogens such as bacteria and protozoa, which could cause gastrointestinal upset.” 

Adding, “Bathing in water containing turbidity may result in an increased risk of skin infections, particularly around the eyes. Or, if the turbidity is linked to a fungal presence in water, even relatively low levels may cause fungal skin infections.”

Which Areas Have The Hardest And Softest Water?

Composed primarily of Calcium and Magnesium, hard water is the bane of many people’s kettles, showerheads and pipes in general. Those living in harder water areas more likely to suffer some form of boiler breakdown than those in soft water areas.

Did you know hard water can also affect the performance of soaps and detergents? It can also cause hair dye to fade faster, and a high level of calcium ions in water can even change the colour of the dye.

Map The Hardest And Softest Water Readings Across England And Wales

Counties with the Hardest and Softest Water in the UK - Homecure Plumbers

Areas with hardest levels of water: Cambridgeshire, Lincolnshire, Northamptonshire, Nottinghamshire, Norfolk, Suffolk, Bedfordshire, Buckinghamshire, Essex

Our research found 9 of the areas analysed had ‘very hard water’, with 16 described as having ‘hard’ water; the majority of the hard and very heard areas being found in East Anglia, the East Midlands, and the South East.

In comparison, the West of England and Wales has the softest water analysed, with much of the North West down to the South West recognised as ‘soft’ water regions. 

Brian Campbell, from Water Filter Guru shares:

“Because hard water is unable to lather properly with soap, it instead forms a layer of soap scum that can build up on your showerheads, faucets and fixtures. Unsurprisingly, if you’re showering in hard water, your skin will also be covered with a layer of this soap scum.”

“This film of hard water can also clog your skin’s pores and has been linked to breakouts and skin conditions such as acne and eczema. Hard water can also be quite tough on skin, stripping its natural moisture and resulting in itchiness and dryness.”

“Overall though, the biggest issue with hard water is most definitely its effects on skin and hair. If you shower in hard water daily, you may experience dry, brittle hair that’s prone to breaking, and dry, itchy skin that’s prone to breakouts.”

Which Areas Have The Most ‘Impurities’ In Their Water?

By analysing the legal percentages of the ‘impurities’ in the water quality tests, we were able to build a picture of the areas of England and Wales with the highest average level of impurities. 

Our analysis found that South London, and bordering East Surrey and West Kent, have the lowest quality of water analysed. This is due to their results having the highest average rate of impurities and elements against legal limits. 

According to our analysis, water in the three areas has an average rate of impurities and elements of 21.8%. Meaning, that readings of impurities and elements were on average 21.8% of legal limits.

Areas of the UK with Highest Average Impurities - Homecure Plumbers

Conversely, our analysis found Flintshire and Denbighshire to have the lowest average rate of impurities in water quality tests. With the average reading just 4.55% of legal limits, followed by Shropshire and Powys (5.5%). 

Areas of the UK with Lowest Average Impurities - Homecure Plumbers

The UK’s Water Quality

Lee Devlin, Founder, at Homecure Plumbers in London comments:

“Overall, our research has shown how the water companies have managed to keep all our water within safe limits when it comes to heavy metals and other imperfections that could have detrimental impacts on health, appearance or even the very utensils we use for our water.

“Ensuring water is safe, treated and clean of potential contaminants is no easy feat, with many variables based on geography, land usage and even the actions and infrastructure of our ancestors having an impact on how our water reaches us today.”

“Our research highlights just how different the water compositions and across much of England and parts of Wales are, with one of the biggest surprises being the (although safe) levels of lead in South London and West Sussex compared to the other areas analysed.”

Data Sources & Methodology


Data was taken from the most recent (2020) water quality reports for each water authority analysed and their subsequent areas and regions of coverage. Where counties and water authorities crossed over, an average (central postcode) was used to provide an average estimation for that area. 

Elements and contaminants analysed were chosen due to their prevalence, impact on water taste and flavour, and potential health impacts. 

We thank Brian Campbell for his assistance and help in the production of this piece. Brian Campbell is the founder of, where he blogs about all things water quality. His passion for helping people get access to clean, safe water flows through the expert industry coverage he provides.

Data Sources

  • Water quality postcode search (


Lee Devlin
Publication date: 17/03/2021

Lee Devlin is the managing director of Homecure Plumbers, London's favourite local plumbing service. Since 2009, Lee's been leading a large team of gas safe plumbing and heating engineers as well as growing a successful business built on quality customer service and workmanship, in a competitive industry within the Capital. He's been in the game for a long time, so he regularly shares his knowledge and experience with the public. His expert tips have been featured in lots of well known publications such as: The Sun, Metro, Insider, Homes And Gardens, Country Living and more!

Read More About Lee Devlin.

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