Stormwater is rainwater that flows across roofs, roads and driveways into the stormwater system. Stormwater is not treated to remove any pollutants.

Wastewater is the dirty water from houses and businesses that is flushed or sent into the wastewater system. Wastewater ends up at a wastewater treatment plant where the wastewater is treated, solids removed and the liquid or effluent is discharged to the sea.