I’m looking for a small, fast growing, evergreen tree (9-15′) to provide filtered shade.

Question

I live in zone 9-10. It would be near my sewer pipes, so need non-invasive root system.

Answer 1

I'm sorry. I can't recommend any tree to go near a septic system. Even if roots aren't invasive, they can still displace soil near and around the sewer system. That can cause bends, leaks and breaks.

There are plants that are considered safe to plant near septics, but not very many trees will be safe to do so.

This article will help: https://www.gardeningknowhow.com/edible/vegetables/vgen/gardening-over-septic-tanks.htm

https://www.gardeningknowhow.com/ornamental/flowers/fgen/septic-field-plant-choices.htm