Where do I look for water entering

[270]

The pump evacuates water once an hour 

[jwestonlee]

Check the raw water intake for leaks. Also, you may want to check your freshwater tank/hoses. Also, check all your engine coolant hoses for leaking attachments - typically a loose hose clamp. I'd make this a priority project. 

[msr]

It may just be seeping back in past the check valve ..

[drycleaner]

Shaft logs?