Thanks for your responses, they are really helpful. I contacted the building company and they are sending out an independent plumber next week to carry out some tests on the header tank water.
I'd be grateful if anyone has any advice on the following: I bought my house from new, just over 4 years ago. Yesterday, one radiator sprung a leak and the liquid that came out was a really dark colour. On inspecting the header tank in the loft, it contains slimy deposits, like algae, and is obvious...
