We were called on Saturday to repair an immersion water heater in St. Albans, at a client for which we repaired also a storage heater not long ago.
The electrical engineer drained the water heater tank and removed the elements in order to replace the faulty elements that were impairing the clients from having hot water. When he extracted the botton element from the water heater tank, together with it a wave of chalk emerged from the tank. It was a shock even for our experienced engineer, which has repaired lots of water heaters before in the London area, to see so much limestone sediments. It is a known fact that in St. Albans, and in London for that matter, the water is hard to very hard http://www.bristan.com/watermap but to see a water heater tank so full of sediments was unexpected.
You cannot change the water if you leave in London area or in the vicinity, but what you can do is to have your electric water heaters and other electrical appliances that run on water serviced by an expert electrician, like the ones employed by Storage Heater Repair, a trading name of London Electricians, for which no task is too hard and can manage in any situation.