Anyone know where the water heater is usually located on a 46?

Under the back seat starboard side

Thats where I thought. No water heater installed. I can see the pex tubing running from the galley sink and the head sink towards the rear of the boat but it just disappears into the boat somewhere. I'd like to put a water heater in but have no idea where to access the piping. Any idea where the tubing goes once it leaves the faucets?

OK found the water heater. Its behind a false front under the seat. Thanks

There's a 120v switch located on the panel in the cabin labeled "accessory" - anyone know what this switch operates? I'm thinking maybe the water heater?