I put 1-5 but it's probably more. It can be 'lumpy' depending on circumstances.
I serve on a local planning group subcommittee that requires extensive research. I also attend the main planning group committee and contribute (though am not an elected member.) I sit on a working group for the largest capital project our city has ever done that is impacting our neighborhood. I advise a local community group, though have declined a board position. When big projects come up in our area - I often get tapped to dissect the environmental impact reports (very long, very dry documents) to see what might be hidden. Then, if necessary, participate in groups testifying before the planning commission and city council. That can be a lot more hours.
I also proctor ap and IB tests at my kids high school, and help with fund raising for the kids HS swim team.
Most weeks it's 1-6 hours... but every now and then it cranks up to 30-40 hours/week.
Edited to add - does helping moderate this forum count?