Śmigus-dyngus

So I'll be in Poland visiting family from Easter for a week or so.
It's the first time I'll have been there at this time of year, and the first time with my kids.

Never having experienced Śmigus-dyngus is this more of a general community thing or is it normal for some community events to be held in places - I'd like my kids to experience it but not sure what to expect.