This document discusses providing low-cost, effective perimeter security for water and wastewater facilities using Crime Prevention Through Environmental Design (CPTED) principles, sustainability concepts, and new technologies. It advocates a deterrent approach to security and utilizing natural surveillance, access control, and territorial influence. Wireless mesh networks, IP cameras, and solar-powered devices are presented as technologies that can support CPTED strategies while reducing costs, environmental impact, and infrastructure needs compared to traditional security systems. The document argues this integrated, sustainable approach can strongly deter crime and protect critical infrastructure at water/wastewater sites.