Some dockside activities and equipment are particularly serious backflow risks because of the types and quantities of possible contaminants or the likelihood of backflow conditions occurring. These include:

• filling of ships' drinking water tanks
• refuelling and general water loading points
• dry docks - especially maintenance work on plumbing systems
• sewage disposal
• fish houses and markets
• pressurised systems and equipment for non-drinking water
• fire-fighting systems using other than mains water