Have I done something wrong? I ma filling up my fresh water but it appears to be draining into my waste water tank without first going through the taps. I filed up yesterday and drained the waste but now the fresh water is half full and the waste has a load of water in it. Please help!

How bizarre !!!

There is NO physical connection between the two other than via the drains from your sink/shower etc.

Was your vehicle parked on a slope?? as that could mean there was water still in the waste tank when you thought it empty.

As far as the fresh tank is concerned it is not at all uncommon for a fair bit to be "lost" whilst under way. I had that with a couple of Autotrails, the fresh tank has a hole at the top for equalisation of pressure when some is drawn off. Water sloshes from side to side and, over the course of a few roundabouts, a lot escapes. In my case often around 20%. I soon stopped travelling with a full tank!!!

Also was the hot water boiler full when you filled your fresh water tank?? If not the first time you switch the pump on it will take 11-14 litres to fill it !!

Is your pump running without you knowing ??? i.e a tap left slightly on, or the shower head lying on the floor BELOW the level of water in the fresh tank and it thereby siphoning out and down the drain ?

Andy

How do you know that the fresh water is only half full and similarly with the waste water? Are you relying on the gauges? - it's not uncommon for them to stick and give inaccurate readings.