What model year is it?
I've had a similar problem in my '06 LR3 (all the gory details in this thread: I seem to have a small lake in my '06 LR3
The list of water sources includes:
Sunroof drains being clogged
Sunroof drain lines getting kinked
A leaking windscreen cowl -- especially that nice little dish the passenger side wiper sits in -- often after a windscreen replacement.
The drain tube to the HVAC coming disconnected
And what turned out to be my problem: the A pillar leaking. This was caused by the A pillar being swapped out (by the dealer I bought it from) and the requisite patches not put in place.
You do want to get that fixed and get the carpets and under-carpet insulation dried out as one of the main wiring trunks runs under the passenger-side carpet. Electricity and water don't play well together.