collected rainwater

基本解释

Squirt gun mounted on the handle of an umbrella self-recharges from collected rainwater. [link]
这把雨伞在伞柄处配备了水枪的功能，可以从雨伞上收集到的雨水充盈于伞柄【作为发射之用】。
Instead of a pot of gold at the base of each rainbow there lies a storage tank of collected rainwater, which McKean saves for next time.
在每道彩虹的下面并非一盆金子，而是收集雨水的蓄水箱，McKean 用它来供下次使用。
are attached to the exterior of the building and the collected rainwater is stored in an underground cistern to be later used throughout the vertical community.
薄膜太阳能电池安置在建筑的外表面，收集到的雨水储存在地下蓄水池里，供日后整个垂直社区使用。

That made it easier to purify the rainwater that in Singapore is fastidiously collected wherever it can be—in streets and ponds, even on tall buildings and bridges—before being taken by drains to reservoirs, and thence to treatment plants where it is cleaned to drinking-water standards.
ECONOMIST: Every drop counts The
Meanwhile, rainwater would trickle down the curved exterior of the four-level home where it would be collected, then purified, for drinking water.
FORBES: 10 Floating Homes Of The Future