The 36-gallon fresh water tank on a 2002 Maxum 3300 SCR is located under the floor of the cabin, specifically beneath the floorboards in the mid-cabin/aft berth area.
To access the tank and its associated water pump, follow these steps:
- Locate the access panel: Look for the forward floor panel on the aft berth floor.
- Remove the carpet and screws: You will need to pull back or remove the marine carpet to locate the panel. The sump pump/tank wood panel is typically secured with a few screws and a small amount of adhesive.
- Slide the panel: Once the screws are removed, carefully slide or lift the panel back towards the aft wall to gain access to the tank.
Review this thread:
3300-scr-fresh-water-tank-leak-repair-or-replace-tank-by-removing-aft-floor