It could be caused by many things. Iron or mangnaese can cause that complaint. Galvanized plumbing or fittings too. What is your water source, city or well? Have you had the water tested, if so what were you told the water contained? Do you see any rusty type staining?
Gary, thanks for your reply. I have previously asked a couple of plumbers that have come to do other jobs about the taste, with no luck. We are in Canberra. The house was built in 1969. I don’t know what type of pipes/fittings we have. Where can we get our water tested? If the problem is as you suggest, what are the solutions?
Mike, I’m in the US and here we would look in our phone book yellow pages under the heading Water Conditioning, treatment, filtration etc. and call a water treatment guy/gal. Another is the heading Water Analysis or Water Testing Labs.
Re-reading your initial post I see you say when the water sits it has the taste, what about fresh out of the spigot? If not, then I’d guess oxidation of iron, manganese etc. might be happening in the glass and that could be the cause of the metallic taste. Have you sanitized any water container you use in the ‘fridge to store your water in to chill it? Clean it first with a brush etc. and try some non-scented bleach and fill the container, then let it sit for about 30 minutes, then rinse well and see if that helps.