Planting some trees in my front yard

I want to plant a couple fruit trees in my front yard but I’m not sure how far from my sewer line or far from my house they need to be. I looked up my house on DSO Water and Sewer Map so I know at least roughly where the sewer line is. Is there a city office I can call to get some advice or do I have to hire an arborist or what? One confusing thing is that there is an older tree already in our front yard that seems to be directly in the path of the sewer line, which seems like it should be a problem, but it has obviously been like that for at least 30 years. Maybe if the sewer line is newer than the tree it could be on top of the roots? Any pointers are appreciated. Thanks