Mains

Tap water

Written by the VitaWhat editorial team · Medically reviewed by Steve Davis · Last reviewed 19 July 2026 · Editorial policy

Treated public drinking water piped to homes — safe, cheap and regulated.

Where it comes from

Drawn from reservoirs, rivers or groundwater, then treated at a water works (screening, filtration, disinfection) and piped to homes.

What it contains

  • Small amounts of dissolved minerals (calcium, magnesium)
  • A trace of chlorine (added to keep it safe)
  • Fluoride in some areas (added or natural)
  • Very low, regulated traces of nitrates and metals
  • Hardness varies by region

Benefits

  • Extremely cheap and low-waste (no plastic)
  • Strictly tested and regulated in the UK
  • Provides some calcium and magnesium, especially in hard-water areas

Cautions

  • Taste of chlorine puts some people off (a jug filter or letting it stand helps)
  • Old lead pipes in a few very old homes can add lead
  • Hardness causes limescale (harmless to health)

Sources & references

  1. WHO — Drinking-water
  2. UK Drinking Water Inspectorate

Related entries

Alkaline waterArtesian waterDeionised waterDistilled waterFiltered waterGlacier / iceberg water
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