Dry wear flow is wastewater flow in sewers during dry wear. Dry wear flow in combination with stormwater is called as wet wear flow.

Dry wastes such as dry leaves, paper and grass are called garbage. Discharge is outflow of water or wastewater. Sewage is wastewater from various houses. Sullage is wastewater from bathroom, kitchen, wash basins, etc.

The quantity of sanitary sewerage entering sewers would be less than total quantity of water supplied because water is lost in domestic consumption, evaporation, lawn sprinkling, fire fighting and industrial consumption.

An aquifer is an underground layer of water-bearing permeable rock, rock features or unconsolidated material from which groundwater can be extracted using a water well.

The common unit used to express rate of water supply to a city or town is in terms of litres per person for a day. Capita refers to each person or an individual. Hence unit is litres/capita/day.

Urban cities have a large area and high population, refore water usage is more and sewage generated will also be more. Hence, a separate system to carry sewage and stormwater is necessary. Whereas in rural areas, precipitation will be absorbed by ground and infiltered. Therefore only a little amount of precipitation forms storm. Hence combined system is preferred.

Different treatment plants produce different quantities of wastewater depending upon water needs and usage within industry. The quantity of wastewater in sewer depends upon population in that area and water usage. Hence proper assessment should be made considering both peak and normal conditions.

A fire hydrant also called as a fire plug is a connection point by which fire fighters can tap water from a water supply. It is a component of active fire protection. It helps in emergency situations and rescues.

The overall purpose of sanitation is to provide a healthy environment for all and to provide safety, security and dignity for people when y defecate or urinate, not to just maintain a green environment alone.

The rate of usage of water varies from individual to individual and different sectors. Hence total quantity of water supplied is equal to rate of supply multiplied by population.