Tap Water in RG27
Surrey Hills — South East Water
Tap water in Surrey Hills, supplied by South East Water, has the character of a chalk aquifer source, typical of southern and eastern England. It's moderately soft, in the lower end of the national range, with a total hardness of 103 mg/L as CaCO₃. Bicarbonate is high at 328 mg/L: this water suits dark-roasted, milk-based coffee well, but will strip the acidity from lighter roasts and pour-over brewing.
Mineral composition
| mg/L | |
|---|---|
| Calcium | 107 |
| Magnesium | 4 |
| Sodium | 22 |
| Sulfate | 54 |
| Chloride | 47 |
| Bicarbonate | 328 |
Additional info
| Hardness | 103.13 as CaCO₃ |
| Alkalinity | 269 as CaCO₃ |
| pH | 7.52 |
| Conductivity | 597.48 µS/cm |
| Source | South East Water |
| Data year | 2025 |
What this means
Kettle & appliances
Some light mineral residue may appear in kettles over time, but significant limescale buildup is unlikely. No treatment needed for most appliances.
Espresso
A good range for espresso. Enough mineral content to provide body and balance acidity without posing a real scale risk to the machine. Most specialty coffee water targets fall in or near this band.
Filter & pour-over
Excellent for filter brewing. The slight mineral content adds body and sweetness without masking acidity, giving a balanced cup across most roast levels. This is close to the SCA's recommended range for brewed coffee.
Drinking & cooking
Tastes clean with a slight mineral presence. Good all-round water for cooking; it won't interfere with delicate flavours or leave noticeable deposits.
Bicarbonate
Heavily buffered water that resists pH change substantially: suited only to the darkest, most roast-forward beer styles (and even then may need dilution), while espresso at this level will taste dull, chalky, and lacking definition, with almost all origin character neutralised by the alkalinity.
Closest water profiles
Nearby areas
Data sourced from South East Water (2025). Looking for a specific address? Look up your full postcode for the most accurate result.