Editorial remarks.-- Open discussion: Regulation under the public model of service provision ; Regulatory progress and challenges in Argentina ; Twenty years of SUNASS: development, experience, lessons learned and challenges ; Possible conflict between efficiency and sustainability ; Best practices in regulating State-owned and municipal water utilities.-- News of the Network: Water use charge in the Province of Buenos Aires ; National Drinking Water and Sanitation Sector Policy of Guatemala ; Sanitation Services Modernization Law of Peru ; Internet and WWW News