background
canal
channel
conduit
construction
culvert
current
ditch
drain
drainwater
environment
flow
flush
grunge
grungy
hole
industrial
industry
inside
manhole
metal
mud
open
pipe
pipeline
pit
pollution
pour
pouring
river
round
sanitary
sewage
sewer
sewerage
stream
structure
system
treatment
trench
tube
tunnel
underground
wall
waste
waste water
wastewater
water