drainage
US /ˈdreɪ.nɪdʒ/
UK /ˈdreɪ.nɪdʒ/

1.
the action or process of draining something
:
•
Proper drainage is essential for healthy crops.
•
The city invested in a new drainage system.
2.
a system of drains
:
•
The old house had poor drainage.
•
They are working to improve the drainage in the area.