Rainwater from the roof is collected and funneled into a 25,000 gallon underground cistern . Wastewater from showers , sinks and toilets goes into underground purifying tanks and then into the cistern . The collected water then irrigates the land surrounding the house . Surrounding flowers and shrubs native to the area enable the property to blend into the surrounding rural landscape .
Why might this system have been designed ?
Pick the best answer from the following options:
- It is a source of alternative energy .
 - It is an attempt to create water .
 - It is an attempt at off - grid living .
 - It is a source of clean drinking water .


It is an attempt at off - grid living .