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 .
According to the above context, choose the best option to answer the following question.
Question: What might this water system be used for ?
Options:
- It may be a way to increase utilities .
 - It may be a zero - waste watering system .
 - It may be a way to get access to more water .
 - It may be a way to purify city water .


It may be a zero - waste watering system .