Water in fuel indicator

[Eagerbilt]

Thanks for the add Rawze...great job on this forum.

I own a 2014 Pete 389, mandate NOT removed...ISX15.

Was getting a check engine fault which I was sure was for the after treatment and I was right (but it’s minor)...but one other fault I didn’t expect was water in fuel. There’s no coolant sitting in the fuel filter and the truck is running as expected...the code was inactive when the dealer plugged in, there was 12 counts at the least severe level.
There was a bit of cause for concern from a buddy mechanic of mine, but he told me it should be fine once I checked the filter...so here I am. Was wondering what else I can look for myself and how much I should be concerned about this?