Mr Squirrel,

I had a similar issue and found the leak at the filler tube/tank
junction. Water got under the cabinet and it could have been bad news
if not noticed right away. A bit of tightening of the band clamp did
the trick. The shop vac came in handy to suck most of the water from
all the nooks and  crannies. Westies sure have a lot of nooks and
crannies!

You may also want to check the other end of the filler hose and the
vent hose connections. The tank lid and pump hose grommet, 12v pump
lead grommet, too.

Keith O