Tap Water in PO31
Your water is pumped from underground sources in the chalk at Carisbrooke and th — Southern Water
Tap water in Your water is pumped from underground sources in the chalk at Carisbrooke and th, supplied by Southern Water, has the character of a chalk aquifer source, typical of southern and eastern England. It's moderately hard, in the upper half of the national range, with a total hardness of 270 mg/L as CaCO₃. Bicarbonate is high at 284 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 | ~99 | ||
| Magnesium | ~5 | ||
| Sodium | 14 | ||
| Sulfate | 16 | ||
| Chloride | 36 | ||
| Bicarbonate | ~284 | ||
| ~ Estimated from hardness and ion balance — not directly measured by the water company. | |||
Additional info
| Hardness | 269.7 as CaCO₃ |
| Alkalinity | 232.7 as CaCO₃ |
| pH | 7.29 |
| Conductivity | 544.80769 µS/cm |
| Source | Southern Water |
| Data year | 2024 |
What this means
Kettle & appliances
Limescale buildup is noticeable and ongoing. Kettles will develop visible deposits within weeks, and heating elements in boilers and washing machines will need periodic attention. A water softener or scale inhibitor is worth considering.
Espresso
This water will scale espresso machines meaningfully. Flavour-wise, the high mineral content tends to flatten acidity and produce a heavier, less nuanced shot with lighter roasts. Darker roasts and milk-based drinks fare better: the body and density that hard water produces can carry well through milk. Regular descaling is essential, and filtration or blending with softer water is worth considering.
Filter & pour-over
The effect is more noticeable here than in espresso, because the higher water-to-coffee ratio amplifies the mineral influence. Lighter roasts will taste muted and uniform; origin character gets buried. Darker roasts hold up better, but the cup will lack the clarity that filter brewing is best at producing.
Drinking & cooking
The mineral taste is perceptible. Some people prefer it; others find it chalky. Hard water can affect how well soap and detergent lather, and it leaves visible residue on glass and stainless steel.
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 Southern Water (2024). Looking for a specific address? Look up your full postcode for the most accurate result.