What is lurking in my tap water? A UK contaminant guide

Water quality is getting more attention than it has in decades, and rightly so. As health awareness grows, more people are realising that living well starts with the quality of the water they drink, not just the quantity. Good food matters enormously, but it comes second to clean, living water.

UK tap water is legally safe. That is a genuine achievement and worth saying plainly. But "safe" is a regulatory threshold, not a health optimum. Public treatment is designed to deliver water that meets Drinking Water Inspectorate (DWI) standards at every tap from Penzance to Poole, which means it arrives disinfected, chemically stabilised, and carrying whatever it has picked up on the journey through decades-old mains.

So let's look honestly at what may be coming out of your taps if left unchecked.

1. Chlorine and chloramine

Chlorine is added as a disinfectant, and without it water companies could not move water through miles of pipework without bacterial and algal growth. It has a job to do, but that job ends at your stop tap.

Chlorine is a reactive chemical. It strips the natural oils from skin and hair, which is why eczema and psoriasis sufferers so often report improvement after installing a filter. It affects taste and smell, ruins tea and coffee, and kills beneficial bacteria. Many UK areas now use chloramine (chlorine bonded with ammonia) instead, because it persists longer in the network, which also makes it harder to remove and means it does not simply evaporate if you leave a jug on the counter.

2. Disinfection by-products (THMs)

When chlorine meets organic matter, peat, leaf litter, algae, it forms trihalomethanes and other by-products. This matters especially in the South-West, where much of our supply comes from peaty upland reservoirs on Dartmoor, Exmoor and Bodmin Moor. High natural organic content plus chlorination equals higher by-product formation. These are regulated and monitored, but they are not something anyone wants in their glass by choice.

3. Lead

Lead is the big legacy problem in British housing. Any home built before 1970 may still have a lead supply pipe or lead-soldered joints. Corroding pipework can release lead into standing water, and lead is toxic to virtually every organ, with children affected worst: developmental delay, learning difficulties and behavioural problems are all documented outcomes.

Water companies dose with orthophosphate to line pipes and reduce leaching, but that is mitigation, not removal. If you live in a Victorian or pre-war property, this alone is a strong reason to filter at the incoming main.

4. Fluoride

Fluoridation began in the 1940s to reduce tooth decay. Around 10% of the UK population receives artificially fluoridated water, mainly in parts of the West Midlands and North-East, with expansion proposed. Others receive naturally occurring fluoride from the geology.

Whatever your view on the policy, fluoride is a substance many people would prefer to choose for themselves rather than receive by default. Several European countries have discontinued water fluoridation on exactly that consent basis. Standard carbon filtration reduces it only partially, removing it properly requires the right media, which is why system selection matters.

5. Nitrates and agricultural runoff

Somerset, Dorset and the Levels are intensively farmed. Nitrate from fertiliser and slurry leaches into groundwater and takes decades to work through an aquifer, so today's readings reflect farming practice from the 1990s. Several South-West groundwater sources are formally designated as at risk. High nitrate is a particular concern for infants and pregnant women.

Alongside nitrate come pesticide and herbicide residues, metaldehyde from slug pellets was a persistent headache for water companies for years precisely because conventional treatment struggles to remove it.

6. PFAS, the "forever chemicals"

Per- and polyfluoroalkyl substances are used in non-stick coatings, waterproof fabrics, firefighting foam and food packaging. They do not break down. The Royal Society of Chemistry has publicly called for tighter UK limits, and testing has found PFAS in drinking water sources across England, including sites near airfields and industrial land.

Activated carbon and reverse osmosis are the practical household defences. This is the contaminant class that has changed the conversation about home filtration in the last five years.

7. Microplastics

Studies consistently find microplastic particles in bottled water, roughly 90% of samples, averaging around 10 particles per litre. Tap water fares better but is not clean: fibres and fragments have been found in supplies worldwide. Ironically, switching to bottled water to escape tap contaminants increases your plastic exposure.

8. Pharmaceutical and hormone residues

Medication that passes through the human body enters the sewage system. Treatment works were never designed to remove pharmaceutical compounds, and trace levels of painkillers, antidepressants, antibiotics and synthetic hormones have been detected in rivers and, at lower concentrations, in drinking water. No one is claiming a clinical dose. But nobody chose it either.

9. Heavy metals and sediment from the network

Beyond lead, ageing iron mains contribute rust and micro-sediment, and copper can leach from internal plumbing in soft-water areas. Cornwall's naturally soft, slightly acidic water is more aggressive to copper pipework than hard water is. If your water occasionally runs cloudy or leaves a metallic aftertaste, this is usually why.

10. Limescale, the one you can see

Calcium and magnesium are not toxins; they are minerals your body needs. But dissolved at hard-water concentrations they cost you real money. Bath, Bristol, Wells and the Mendips sit on limestone and chalk, giving some of the hardest water in Britain. Just 1.6mm of scale on a heating element cuts efficiency by around 12%, and untreated systems can lose up to 40% efficiency over four years.

Things that do not work

• Boiling. It kills organisms. It does nothing for metals, salts, PFAS, nitrates or chemical compounds, and by evaporating water it slightly concentrates them.
• A fridge jug filter. Useful for taste at one tap. It does nothing for the shower you stand in, the bath your children use, or the boiler heating your home.
• Bottled water. Expensive, plastic-heavy, and as noted above, a reliable source of microplastics.

What actually works

Filter at the incoming mains, so every tap, shower and appliance in the property benefits from one system:

• Sediment pre-filtration to catch rust, grit and particulates from the network.
• High-grade activated carbon for chlorine, chloramine, THMs, pesticides, PFAS and taste.
• Salt-free scale control to stop limescale forming without adding sodium or stripping useful minerals.
• Remineralisation and revitalisation. Grander® technology restructures the water so it behaves the way spring water does, rather than merely being stripped of everything.

That sequence is the basis of the P.R.A.E. approach we build every install around: Purify, Restructure, Activate, Environment.

Which system for which problem

• Hard water, Bath / Bristol / Wells / Frome: Pureau 2, filtration plus salt-free softening.
• Older property with possible lead pipework: filtration-first with certified heavy-metal reduction media.
• Soft-water Cornwall and West Devon: EcoPure 1H+ plus Grander®, the focus is chlorine, by-products and structure, not scale.
• Larger or high-occupancy homes: Pureau 3 for the flow rate and cartridge life.

Not sure where you sit? Run your postcode through our water checker for a picture of your local supply, then take the two-minute system finder and we will match a system to your property, your bathrooms and your water.