What percentage of domestic wastewater is water?

The correct response indicates that approximately 99.9% of domestic wastewater is water. This high percentage reflects the nature of domestic wastewater, which primarily consists of water from various household sources, including sinks, showers, toilets, and washing machines.

Understanding the composition of domestic wastewater is essential for wastewater treatment processes. The significant water content informs how treatment systems are designed and operated, as the primary focus is on removing contaminants from this predominantly water-based mixture.

While other figures, such as 90%, 80%, or 70%, may seem plausible at first glance, they do not accurately represent the typical composition of domestic wastewater. The 99.9% figure is consistent with empirical studies and industry standards, emphasizing the critical role of effective treatment processes in managing the small percentage of waste material that needs to be addressed.