Describe each result
List toilet, basin, shower or other fixtures actually connected if known. State whether only one drains slowly or all change together.
Avoid assumptions about capacity
The model's intended connections matter. An engineer can screen existing repair work with that information; this does not establish that added fixtures or a new installation would be suitable.
A useful distinction
If a fixture was added recently, state that history without assuming compatibility. Existing repair assessment cannot confirm that the unit was correctly selected for every connection or offer a new installation design.