Final answer:
The question relates to Mathematics and involves calculating the volume of rainwater collected and used, appropriate for Middle School. Measurement in liters or kiloliters is appropriate given the large volumes discussed, and the context includes sustainable water use and conservation practices.
Step-by-step explanation:
The student's question involves tracking the amount of rainwater collected and used, which falls under the subject of Mathematics. This seems suitable for a Middle School level as it deals with basic arithmetic and understanding of capacity measurements. The way that water usage is represented in the question suggests that we are dealing with metric units of volume, specifically liters and possibly kiloliters for larger amounts.
Since the question indicates that the amount of water a family uses in a year can be quite substantial, akin to the water in a swimming pool, measuring such volume in kiloliters would be appropriate. This aligns with how water withdrawal is considered on a larger scale, where percentages of total available water are used to gauge usage and sustainability.
Practical applications of water collection, like using rain barrels to collect rainwater for gardening, highlight everyday methods of resource conservation. This knowledge can be linked to broader topics such as sustainable water cycles and conservation methods such as the reuse of gray water and the implications of water shortage on agriculture, as indicated in the given references.