Define "gray water" in plumbing systems.

Gray water refers specifically to wastewater generated from domestic activities such as washing dishes, taking showers, and doing laundry, which does not contain significant amounts of harmful contaminants. This definition distinction is crucial within plumbing systems as it highlights the potential for gray water reuse. Unlike black water, which comes from toilets and contains pathogens and high levels of organic material, gray water can often be treated and recycled for non-potable uses, such as irrigation or flushing toilets. This understanding of gray water plays an essential role in water conservation efforts and sustainable plumbing practices. The other options describe different types of water; for instance, potable water that is safe to drink does not fall under the definition of gray water, nor do agricultural irrigation waters or sewage, which represents more contaminated water sources.