The document discusses Amsterdam's water supply and waste water systems. Amsterdam has an extensive system of canals dating back to the 17th century that was used historically for transportation and defense. The city developed a circular ring system of main water pipes surrounded by distribution areas to ensure reliable water delivery. Waste water from households and industries is collected via pipes and conveyed to a central wastewater treatment plant east of the city. The systems utilize various types of pipes including steel, PVC, and glass depending on the application.