Yes — based on Thames Water's own published data, London tap water is safe across 10 of the 11 metrics we analysed. The one gap: virus count isn't tested or reported. Here's the full breakdown, using four samples taken across East, West, North and South London.
Total Dissolved Solids (TDS)
TDS indicates water hardness — the higher the value, the harder the water. The WHO rates under 300 mg/L as excellent, 300-600 as good. Thames Water's own figures ranged 270-277 ppm, but our independent samples averaged 316 ppm across the city: North London 320, West London 280, South London 350, East London 315. Verdict: safe.
pH Level
The WHO recommends a pH between 6.5 and 8.5. Across 36 samples, London averaged 7.6, with every reading inside the safe range (North 7.7, West 7.7, South 7.6, East 7.7). Verdict: safe.
Bacteria Count
The WHO limit for common water-borne bacteria (Clostridium perfringens, coliform bacteria, E. coli, enterococci) is 0 per 100mL. Across 403 samples in all four areas, none were detected. Verdict: safe.
Chemical Contaminants
- Chlorine — limit 4 mg/L, found 0.98 mg/L.
- Lead — limit 15 µg/L, found 2 µg/L.
- Fluoride — limit 1 mg/L, found 0.15 mg/L.
- Mercury — limit 1 µg/L, found 0.07 µg/L.
- Arsenic — limit 10 µg/L, found 1.2 µg/L.
- VOCs (e.g. benzene) — limit 0.1 mg/L, found 0.022 mg/L.
- Nitrate — limit 50 mg/L, found 40.7 mg/L.
All measured well within regulatory limits. Verdict: safe.
The One Unknown: Viruses
Thames Water's public reporting doesn't include viral testing, so we genuinely don't know how London tap water performs on this metric. Independent lab testing would be needed to close this gap.
Conclusion
By the numbers Thames Water reports, London tap water passes on safety. But "safe" and "free of anything you'd rather not drink" aren't the same thing — chlorine, lead, fluoride and nitrate are all present, just within limits, and virus testing simply isn't part of the public record. The Sküma® Water MY™ Station filters your tap water via 3-stage reverse osmosis, independently lab-tested to reduce PFAS, heavy metals, microplastics and chlorine by up to 99.9%, then lets you remineralise it exactly how you want.
Frequently Asked Questions
Is London tap water safe to drink?
Based on Thames Water's own data across TDS, pH, bacteria and chemical contaminants, yes — all tested metrics fall within WHO and UK regulatory limits. Viral contamination is not publicly tested, so it remains unknown.
Is London tap water hard or soft?
London tap water is hard, with a TDS averaging around 316 ppm based on independent sampling — noticeably higher than Thames Water's own published figures.
How can I check what's actually in my tap water?
Contact your water supplier for their published water quality report, or use an independent lab test if you want figures beyond what's officially reported — including metrics like viral contamination that aren't routinely disclosed.
