It is the chalk that is being removed from the Homestall Road Thames Water site, I have been in contact with them for a couple of months now as I am having to have my car washed on an almost weekly basis. I have been told to keep all receipts for car washes and to send them in to Thames Water for payment. I spoke to a man who made a point of telling me that I was the ONLY person to complain about the chalk on my car and on our street, therefore if any of you are in a similar situation and have this white chalk covering your car or street private message me and I will forward you the telephone number of the man in charge and the address to which you can send your car wash receipts.