water system

nouns

a river and all of its tributaries
water system
is a type of (narrower)
a group of independent but interrelated elements comprising a unified whole
"a vast system of production and distribution and consumption keep the country going"
scheme, system
a facility that provides a source of water
"the town debated the purification of the water supply"; "first you have to cut off the water"
water, water supply, water system