This question already has an answer here:
I have moved into a one bedroom council bungalow a year ago. There has been a very strange smell in the bathroom, it isn't there all the time, in fact there isn't any particular pattern of time when it appears, sometimes morning - sometimes evening. This smell is not bad but it's sickening, smells like an undiluted bottle of Tesco's double strenght blackcurrant juice. It isn't coming from the drains or anywhere else I can put my nose. Trust me, I have cleaned and cleaned to no avail. Suggestions welcome - it's driving me crackers!!