While London’s tap water may not be to the taste of everyone who lives in the capital, it’s absolutely safe to drink, and as for its quality, you’ll find it ranking highly against others around the world. Because the UK’s drinking water safety standards are high, all tap water is safe, but it’s usually the high chemical or mineral elements that can make people think, “Is London tap water safe to drink?”. So, let’s look at some of the processes behind making London tap water safe.

Surface water and groundwater

The tap water supplied to homes in central and greater London and most of the southeast comes from Thames Water. With 5,000 sq. miles of coverage, the water network (and sewerage services) reaches around 15m people, going into residential and business properties across London and the Thames Valley and Surrey, Kent, Gloucestershire, and Wiltshire.

While around 70% of this tap water comes from surface water, which includes reservoir storage, the other 30% is extracted from deep, underground aquifers, also known as groundwater sources. 

Once collected, the water has a comprehensive process of treatments and cleaning before delivering “an average of 2.7 billion litres to nearly ten million people across London and the Thames Valley” (Source). So, once cleaned and treated, what happens next?

Water supply safety

All tap water is subject to Water Supply Regulations. This directive provides safety laws on how water should look, taste, and smell. There are also rulings on chemical content, treatment requirements, and ongoing monitoring arrangements. Following these regulations, Thames Water tests against specific metrics over 500,000 times a year, including:

Total Dissolved Solids (TDS)

Dissolved solids in the water can include natural minerals, including calcium, magnesium, sodium, chloride, and sulfate. The TDS level indicates how hard a region’s water is, and we know London water is classed as ‘hard’ due to its high mineral content.

pH Value

The pH value reflects the water’s scale of acid or alkaline on a scale of 0 - 14. All tap water should have a pH level of between 6.5 to 8.5. A lower pH value means soft water contains more metal than hard water.

Harmful bacteria count

Any harmful bacteria in water, including E.coli and coliform, is bad news, which is why such strict regulations are in place to protect public safety. Thanks to the high safety levels, the regulatory limit for any bacteria in drinking water is a hard 0% per 100ml.

Tap water taste

But why does London water taste different to other parts of the UK? London and the southeast have famously hard water, as it’s been naturally filtered through chalky limestone when extracted from underground aquifers.

Surface water is softer, but when mixed with high mineral groundwater, the mineral content remains high - though that could boost calcium! But if you still don’t like the taste of London tap water, there is a softer, better-tasting alternative.

Pure-filtered for taste and safety

Though tap water comes directly from your mains supply, all our mains-fed water coolers feature advanced mechanical and carbon filtration systems. These enhance water safety and eliminate bad tastes and smells, so you enjoy 100% filtered, great-tasting water at home or in the office.

For more information on all our mains-fed water coolers and our fast same or next-day deliveries directly from our London depot, call our customer service team today at 0208 049 8501. Or email hello@thirstywork.com, and we’ll give you a free quote or get you started on your water cooler 10-day free trial.