Water tank sensor

If both sensors have stopped working it may not be the sensors at fault. Waste sensors are notorious for developing faults. They accumulate fatty deposits and they need to be removed and cleaned regularly. Not had any problems with fresh water sensors. I have fitted extra 230v sockets in an Autotrail, it just depends where you want to put them as to how bigger job it is. I spurred mine off and existing socket to provide a light point in the cab area which once you had the front insulation screen on became too dark to sit in the chairs and read..

peedee

Waste water tank sensors can be cleaned with a biological washing powder or dishwasher tablets dissolved in warm water and flushed down the tank ,then left for 24 hours.Fresh water tank sensors can be descaled with a mildly acidic solution ,like concentrated lemon juice dissolved in water and left for 24 hours.Overfilling the FW tank can damage the electrical connections to the sensors as well.The units are a series of metal rods of varying lengths which are held in a circular,plastic head unit.The rods are prone to gunking up or scaling up in the waste and fw tanks,respectively.They are a pain and I have had problems with the sensors in all three of our motorhomes to date.These days I let waste water run from the tank into a folding bucket and empty it frequently to avoid sensor issues.Fresh water tank is filled to 60 percent and kept at that by regularly  topping up from a spouted,10 litre water container which I bought in France.That way I can just ignore daft sensor readings,for the most part.

Drinking water is fresh from the tap and kept in a lidded jug in the fridge,

I give both lots "the treatment" now and again and they perform OK for a while but inevitably start playing up again after a while.Such is Life and poor design.