Tap Water in RH13
Your water is pumped from the Western Rother River. — Southern Water
Tap water in Your water is pumped from the Western Rother River., supplied by Southern Water, has the character of a blended surface and groundwater supply, with no dominant mineral signature. It’s slightly hard, around the national midpoint, with a total hardness of 160 mg/L as CaCO₃.
Mineral composition
| mg/L | |||
|---|---|---|---|
| Calcium | ~59 | ||
| Magnesium | ~3 | ||
| Sodium | 23 | ||
| Sulfate | 21 | ||
| Chloride | 34 | ||
| Bicarbonate | ~171 | ||
| ~ Estimated from hardness and ion balance — not directly measured by the water company. | |||
Additional info
| Hardness | 159.8 as CaCO₃ |
| Alkalinity | 139.8 as CaCO₃ |
| pH | 7.39 |
| Conductivity | 378.77885 µS/cm |
| Source | Southern Water |
| Data year | 2024 |
What this means
Kettle & appliances
Light limescale will accumulate in kettles and on heating elements over weeks. A periodic descale (monthly or so) will keep things in check, but it’s not urgent.
Espresso
Hardness at this level starts to affect espresso machines more noticeably. Scale will form in boilers over months, and the water’s buffering will round off some of the brighter acidity in the cup. Regular descaling becomes worthwhile.
Filter & pour-over
Filter coffee starts to lose some of its top-end brightness here. Lighter roasts will taste rounder and less distinctive than they would with softer water, though medium and darker roasts hold up well. The cup won’t be flat, but the crispest acidity is softened.
Drinking & cooking
A faint mineral taste may be noticeable if you’re paying attention. Vegetables and pulses cook normally; rice and pasta are unaffected.
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
RH13 tap water works well for baking and aquarium use with little or no adjustment. Espresso and brewing are within reach with salt additions. It has too much mineral content for tea and horticulture; a bottled water blend is the better route for those.
Nearby areas
RH20
Your water is pumped from underground sources in the greensand at Haslingbourne
Southern Water
RH1
Outwood Supply Zone
SES Water
RH14
Your water is pumped from underground sources in the greensand at Haslingbourne
Southern Water
RH15
Butlers Green
South East Water
RH16
Cuckfield
South East Water
RH17
Balcombe
South East Water
Data sourced from Southern Water (2024). Looking for a specific address? Look up your full postcode for the most accurate result.