White Film And Mould Smell In Water Tank

[getonwithit]

Hi ,
My house has two cold water tanks in attic , and very confusing plumbing ,I think two tanks were put in 20 years ago by last owner for waterfall shower due to trickling water soundin one of them I investigated this evening (I think it needs a new bull cock , )noticed the other tank smells mouldy and there is a white fatty film on top layer of water , I'm am thinking the water flow from this tank might have been turned off is this water dangerous ?
Thanks for any advise

[woofgang]

well if its not being used why not remove it?

[The Builder]

I agree with Woofters ............. either remove it, or drain it.

But .............. before you do anything, make sure that it's not a header tank for the central heating.

Also... unlikely, but it may be connected to the other tank, put in to increase the amount of stored water.

[alavahalf]

Have another look at the pipework .. are the two tanks linked together close to the base.
Does the tank with the stale water have it's own ball valve... if so just press it down and you will soon know if it is isolated or not and as TB has already stated it may well be a header tank for the central heating. Plumbers often leave tanks in lofts rather than saw them up to remove them ... they have no value and they will have to get rid of it.

... Funnily enough they no longer leave off cuts of copper pipe lying around..?