I (not at the same time !) drink, boil and wash in the water that comes out the taps at home but in sixty years I have never sterilised or cleaned the taps or pipework in the house, not do I have any idea what lurks in the pipes etc. outside. Therefore, why should I worry about a nice caravanny taste that accompanies my water in the caravan. After all I do cleanse the whole system after each long lay up, including my Aquaroll & Pump etc. Whatever migh be left in the system after flushing, will probably be there forever and is probably harmless anyway. How can you be sure that the bottle your bottled water came in is completely safe or is your own container really clean ? Have you noticed the dead fly at the bottom of a clean glass/cup from out of the cupboard ?
We seem to be getting more and more paranoid about this topic and surely most of our concerns must be really neglibible, especially when you take extra care.