Tap Water in TN21
Heathfield — South East Water
Tap water in Heathfield, supplied by South East Water, has the character of a blended surface and groundwater supply, with no dominant mineral signature. It’s soft water, low in dissolved minerals, with a total hardness of 31 mg/L as CaCO₃. This is notably soft water, among the lowest-mineral tap water in England.
Mineral composition
| mg/L | |
|---|---|
| Calcium | 26 |
| Magnesium | 6 |
| Sodium | 50 |
| Sulfate | 41 |
| Chloride | 42 |
| Bicarbonate | 188 |
Additional info
| Hardness | 31 as CaCO₃ |
| Alkalinity | 154.33 as CaCO₃ |
| pH | 7.86 |
| Conductivity | 386.63 µS/cm |
| Source | South East Water |
| Data year | 2025 |
What this means
Kettle & appliances
At this level of hardness, limescale is essentially a non-issue. Kettles, boilers, and heating elements will stay clean without treatment.
Espresso
Soft water is forgiving on espresso machines (no scale risk) but can produce a thinner, more acidic shot. The low mineral content means less buffering, so bright and sour notes tend to dominate. That said, lighter roasts can shine here in ways they won’t in harder water.
Filter & pour-over
This is where soft water shows its range. A V60 or Chemex will produce a bright, clean, highly readable cup with clear origin character. Light and medium roasts tend to be at their most expressive. It can tip into sourness with very light roasts, but for most specialty filter coffee, this water is close to ideal.
Drinking & cooking
This water tastes clean and neutral. It lathers easily, rinses cleanly, and won’t leave mineral deposits on glassware or cookware.
Bicarbonate
Significant buffering that pushes mash pH high enough to require acid additions for most beer styles other than stouts, and produces espresso that is notably flat and heavy, with muted acidity and a tendency toward a uniform, opaque flavour profile.
Get the best from your water
TN21 tap water works well for espresso with little or no adjustment. Brewing is within reach with salt additions. It has too much mineral content for baking, aquarium use, tea, and horticulture; a bottled water blend is the better route for those.
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Data sourced from South East Water (2025). Looking for a specific address? Look up your full postcode for the most accurate result.