[jyl]

How much maintenance is required for these ponds? In hours/month and type of work, let's say? Are leaves the main hassle, or something else?

Do these ponds attract mosquitos? Suppose you didn't have fish - then would you be breeding mosquitos? What about other wildlife, do you attract coyotes or other undesirables?

Is there a safety hazard (small children, etc)? Any issues with your homeowners insurance?

I've thought of putting a pond and waterfall/water fountain in my yard. To look nice, reduce the amount of grass to mow, and maybe mask the street noise a bit. I don't actually care if it has fish - turtles would be cool though. But I don't want to do more than, oh, 15 minutes a month of maintenance. Or breed mosquitos. Or attract undesirable animals.