We have a sump pump drainage pipe that I need to take 125 ' to a storm sewer outlet. It comes out of the house above grade. I was going to go into the ground 18" and then trench it to the outlet. There is plenty of slope. I was going to use 1 1/2" PVC. I was not going to put rock in the trench. Is this the right approach?

Hi there...
I suggest that you use 4" pipe for better flow. Exit the house with 1 1/2" and connect to 4" ABS or PVC where pipe gets underground. Also, I would install 2 - 4" clean-outs along the way. You can use sand on the bottom of the trench. Make sure pipe is properly supported before you re-fill. Hope that helps. Milo

Unless you are having to pump out lots of water, do you really need to run your drain all the way to the street and did you check to see if that was legal? You might consider a dry well or run the water into a garden or landscaped area.

I think it's legal. The storm drain is actually at the back of the property, not at the road. My concern with a 4" pipe is actually tying it into to the storm drain. Thoughts?

If this is an open culvert, just run the pipe into it. If it is a concrete structure, you may need a permit to cut into the line. Considering the average use, I'd go with a 2" pipe since it's gravity fed.