Is this for hydraulic jacks (typically HWH)? The tank for the jacks is commonly located under or adjacent to the front steps at the entrance door. There is an entire package unit with solenoids ad valves located there that drive the jacks, and the tank is on top of the unit with a screw top that has a dipstick inside.
Check the level with all jacks retracted.
If it is for hydraulic slides or other equipment, the location can vary, commonly in the engine bay.
Hope this helps....
2008 Monaco Dynasty Diamond IV
Cummins ISL 425 8.9L
Towing 2006 Honda CR-V