Peninsulas are exceptional areas loved to be developed uniquely in most part of the globe. Lekki Peninsulas in Lagos, Nigeria is fast growing, benefitting from similar fortunes such as modern residential suburbs, free trade zone, airport; and tourism are springing up but without adequate potable water for sustainable development. Reconnaissance surveys followed by an In-Depth-Interview were carried out. The commonest sources are sachet, bottled and borehole waters. Sachet and bottled waters are readily available but at unaffordable costs. The most frequently available is borehole, but chemical, physical/organoleptic and microbiological analysis show that the compositions are not within WHO permissible standards. Sustainability is in jeopardy. Individuals, organizations and businesses spend average of 15% of their income on treatments to meet acceptable standards. There are needs to bridge the gap between the residents taking untreated poor water and the few that take WHO standardized waters. A Simple Water Treatment Device is recommended. The device consists of four chambers, two pumping machines, alum and chlorine for treatment. It is equipped with 12 to 13 valves (depending on the position of the chambers); and the entire system is powered by electricity. It will control water borne diseases such as typhoid, schistotomiasis, diarrhea and dysentery, hepatitis, cholera and others; potable water will be available for domestic, recreational and industrial uses; enough for use in the Free Trade Zone and at the forth coming airport; the Eighteen Golf Course will not have challenges of potable water; and forces and military formations within and around the peninsula can rely on the source for every use. It is estimated that the system that can provide average of 100,000 liters of water a day will cost N720,000:00, that is, outside the cost of electricity. The system requires regular maintenance. This device could be applied anywhere.