Water dripping underneath van

Without looking all I can tell you is that it's not normal and not condensation.  You have a leak or a drain valve or tap is open.

Difficult to diagnose, but If it's stopped when your turned things off, I'd leave it off. 
Sounds like it could be an issue with the water pressure release valve. Too many
variables to be 100% sure. I'd consider when you last used water, hot or cold etc
and back track from there. The last leak I had, it was just a pipe and coupling had
came loose and water was escaping.

I agree with what has already been said.  More detail is needed to diagnose it properly.  For example, do you have the Whale or Truma water heating system?  Most Forum members will only be familiar with the Truma.  Does the water pump keep coming on when the taps are closed?  If so that would be indicative of a leaking water connection.  I also thought about the pressure release valve.  All hot water systems have one so that as cool water in the tank warms up and expands, it doesn't over pressurise the system.  The Truma pressure release valve is integrated into the drain valve and when it opens, it does so for less than a second releasing a very small amount of water that is barely noticeable.

It's also worth getting under the van to see if the water is coming out of a pipe or through a gas drop hole.

Look in your manual how to drain the hot water tank.
It'll be a lever operated valve, find it.
Now turn everything off
Open the valve, water should flow under the van, much more than your leak.
Now close it again.
You've now cycled it once. Restart everything again, see if it still leaks.
If so all good. If not at least that's been tried...

IanH wrote:Look in your manual how to drain the hot water tank.
It'll be a lever operated valve, find it.
Now turn everything off
Open the valve, water should flow under the van, much more than your leak.
Now close it again.
You've now cycled it once. Restart everything again, see if it still leaks.
If so all good. If not at least that's been tried...

I've just had a squint at a Whale manual should the OP have a Whale and it says water will drip from the pressure release valve which must be opened periodically to clear limescale from it.  So similar to what you are saying

Could be. But 2023 van?
Either way, go on your trip anyway, it's only a drip and France has plenty water!!

Have you found the pressure release valve and tried opening and shutting it as per the Whale manual I read?