Does Radermachera sinica when planted in the ground pose a problem with drains and pipes?

I wouldn't grow any trees near drains. The roots could easily damage them, like they do planted too close to house foundations. Sorry - but if you can't move the tree to another position, I think I would remove it.

Tree roots get into most drains, I have known them to be 28ft. long inside.
The drains can be exposed and more concrete put round them, cutting back the roots without destroying the tree.
Your tree with it's rapid growth may be living on raw sewage.

I am totally unfamiliar with this tree. However, a rule of thumb answer is that a tree can easily have roots that extend OUT equal to the height of the tree. So that a Eucalyptus for an example might have roots that extend 100 feet in all directions. I am seeing one such creature suck the moisture and life from everything else in the garden. . I convinced one employer I work for to kill his tree as it was planted right next to his drain field. (septic) Then I realized that mine was the same. It was deleted.

The huge tree that triggered this killing series is some four feet thick and is also by the owners septic field. It is still there, but the garden suffers. So will the septic field in the future.

Soil types and depths of soil also affect this decision. But always plant your trees as to what they will become, not the five gallon pot you buy.

thanks for the answers - this tree's demise is currently on the to-do list - thanks again