Tap, filtered or bottled water: which do the experts really recommend?
Experts explain the pros and cons of tap, filtered and bottled water, plus what to know about microplastics, PFAS and hard water.
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Experts explain the pros and cons of tap, filtered and bottled water, plus what to know about microplastics, PFAS and hard water.
You may have drunk tap water for decades without a second thought. Then you move house, notice a chlorine taste or read about “forever chemicals”. Would a filter help? Is bottled water healthier?
Drinking enough matters more as we age. Our bodies hold less water and our sense of thirst can weaken, says Dr Sammie Gill, registered dietitian and senior nutrition scientist at the British Nutrition Foundation.
“Changes in kidney function, cognitive impairment (forgetting to drink) and concerns about continence and toilet access can be contributing factors,” she explains.
Most adults should aim for six to eight drinks a day, says the British Nutrition Foundation. Tea and coffee count towards this.
Generally, yes. Tap water is regulated across the UK. The Drinking Water Inspectorate (DWI) covers England and Wales; Scotland and Northern Ireland have separate regulators.
In England, water companies must meet the Water Supply (Water Quality) Regulations 2016, says the DWI.
More than 3.5 million regulatory tests were carried out in England in 2025 and 99.97% met the required standards. Any failure must be investigated by the water company and reported to the DWI. Water is checked for germs and potentially harmful chemicals at treatment works, storage sites and taps.
Its source, mineral content, treatment and contact with household pipes all affect its taste, says Dr Katherine Pond, associate professor in environmental engineering at the University of Surrey.
London generally has hard water, while much of Manchester has softer water. The difference in mineral content can affect how each tastes, says Dr Pond. You might also notice a hint of chlorine, which is used to keep water safe as it travels through the network.
Metallic or bitter flavours may come from household pipes, adds the DWI.
Both are safe, according to the DWI. Hard water contains more calcium and magnesium, but water generally provides only a small proportion of our daily mineral intake, says Dr Gill.
“You wouldn’t rely on water to meet your daily mineral requirements,” she explains. Food is the main source.
Water softeners replace calcium and magnesium with sodium. The DWI advises keeping an unsoftened supply at the kitchen tap, particularly if you follow a low-salt diet.
An unfamiliar taste doesn’t automatically mean the water is unsafe. Water companies may switch or blend sources, particularly in summer, says the DWI. Little-used pipes can make water taste stale or metallic; new fittings and filters can change it, too.
If you haven’t used the tap for several hours, run the cold tap until it feels cool and fresh, suggests the DWI. Report a petrol or fuel smell to your water company and local authority immediately.
Cloudiness is usually caused by harmless air bubbles after work on the water mains, says Dr Pond.
“Cloudy water should clear within 24 hours. If it doesn’t or it tastes strange, then contact the water company,” she advises.
The cold kitchen tap is normally best for drinking because it is usually connected directly to the mains, advises the DWI. Some bathroom taps draw water from a storage tank, where it may stagnate or be affected by household plumbing.
Avoid the hot tap because heated water can collect more metal from pipes and fittings.
Most people don’t need one, says Peter Jarvis, professor of water science and technology at Cranfield University.
What a filter removes depends on the type. Most filter jugs use an activated-carbon cartridge. “Activated carbon can remove some chemicals and metals, as well as the smell and taste of chlorine,” Prof Jarvis explains.
Reverse-osmosis systems remove a wider range of substances, including metals, salts and minerals. This can leave water tasting flat, says Vanessa Speight, professor of integrated water systems at the University of Sheffield. Drinking water should then have minerals added back, adds Prof Jarvis.
Lead pipes are more common in homes built before 1970, explains Prof Speight, and exposure can damage the brain and nervous system, particularly in children. If you suspect your home has them, ask your water company to test the supply and use a filter certified to remove lead until the pipes are replaced, she says.
Personal preference counts, too. “If you prefer the taste of filtered water and it encourages you to drink more, then it’s a worthwhile consideration,” says Dr Gill.
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Clean the jug and replace its cartridge as often as the manufacturer recommends. “If water is left sitting for long periods or the jug isn’t cleaned properly, bacteria can build up,” says Sylvia Anderson, a food hygiene consultant.
Usually, you simply remove the cartridge, then wash the jug, lid, reservoir, spout and seals with warm water and washing-up liquid, says Anderson. Rinse and dry before reassembling. Keep filtered water covered in the fridge, use it within a day and don’t top up old water.
Follow the manufacturer’s maintenance instructions for filters connected to the water supply.
Both must meet safety rules, but they’re regulated differently. Tap water is monitored under drinking-water regulations, while bottled water is regulated as a food, says Prof Speight: “In the UK, where the tap water is of high quality, there is no health advantage to drinking bottled water.”
Mineral levels vary between brands, but most people can meet their needs through food, says Dr Gill. Some people prefer bottled water because it lacks the slight chlorine taste of some tap supplies, adds Prof Jarvis.
Alkaline water has a higher pH than ordinary water, making it less acidic. There’s limited evidence that alkaline water eases acid reflux, so it can’t be recommended as a treatment, says Dr Gill.
Electrolyte water contains added minerals such as sodium and potassium. It may help after intense exercise lasting more than an hour or heavy sweating, but most people get enough electrolytes from food, she explains.
People with heart failure or kidney problems should seek medical advice before regularly drinking electrolyte water, as they may need to limit fluids, sodium or potassium, advises Dr Gill.
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Tiny plastic particles called microplastics have been found in both tap and bottled water. A University of Birmingham study published in 2025 found an average of 40 particles per litre in UK tap water and 37 in bottled water.
Scientists don’t yet know whether these amounts harm our health, says Prof Speight.
PFAS are man-made chemicals used to make products resist water, grease and stains. They break down very slowly, earning them the name “forever chemicals”.
A 2024 study involving University of Birmingham researchers found two of the best-known PFAS (PFOA and PFOS) in more than 99% of 112 bottled-water samples sourced from 15 countries.
PFAS were also found in UK tap water, although the researchers said the levels in most water samples were not a major health concern.
For most people, the experts choose the cold kitchen tap. “Tap water is exceptionally good value for money and of very high quality in the UK,” says Prof Jarvis.
Anderson agrees: “For me, the main message is not that bottled water is safer or that people should be worried about filtered water. UK tap water is already subject to very strict standards.”
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