Section front
Hard water
The Drinking Water Inspectorate's national map puts the Cambridge area in its top hardness band. These pages cover what that does to boilers, cylinders and taps, and what can be done about it.
Cambridge water sits in the national map's top band
Cambridge water hardness falls in the top band on the DWI's national map, over 300 mg/L. It is around 330 mg/L CaCO3 on a secondary data set; ask your water company for your postcode's current figure.
Longer pieces
What hard water does inside a boiler
Limescale in a boiler can build up where hard water is heated. Approved Document L tells installers to treat the feed to water heaters and combi hot-water circuits in hard water areas, but it names no device.
Before fitting a softener in an older house
A water softener in an older house can limit scale, but softened water may leach copper and lead from old pipes. Check the pipes first, keep an unsoftened kitchen tap and ask your water company about notice.
In brief
Scale inhibitors and magnetic devices: what the evidence covers
A scale inhibitor on a combi boiler aims to limit scale on the hot-water side, but Part L names no device and DWI says magnetic devices do not soften water. Ask for evidence and sale-or-return terms.
Descaling kettles, taps and shower heads at home
To descale a shower head in hard water, take it off if it unscrews by hand, soak it in a descaler following the label, then rinse well. Kettles and tap aerators work the same way. Never mix descaler with bleach.
Finding the hardness figure for your own address
For water hardness by postcode, ask the water company named on your bill for your current figure. National maps and websites give only the broad picture, and DWI says not to buy from door-to-door testers.