Groundwater resources are often the main source of drinking water for remote communities, but they are increasingly found to be unsuitable, and a source of ill health in many parts of the world. High annual rainfall in monsoonal regions makes rainwater harvesting an attractive alternative, but lack of infrastructure for capturing and storing sufficient quantities is often restrictive. This study focuses on the coastal region of Bangladesh where groundwater supplying tubewells are progressively found to contain arsenic and high salinity, and where cyclones are a common cause of damage to infrastructure. The aim of this study is to evaluate the potential of a village scale rainwater harvesting scheme as a solution to water security concerns. Analysis of various size rainwater storage systems (RSS) is conducted using daily rainfall data from Khulna Station in Bangladesh. It was found that a village scale RSS with 3 m deep and 100 m by 100 m surface area could supply 100 L/p/d for 85% of the year. The reliability could feasibly be increased to 100% with seasonal water restrictions. The village scale RSS is compared with an individual household level RSS. Advantages of the village scale RSS include the opportunity for improved management and water quality monitoring, and the potential for public-private partnerships. The proposed methodology can be adapted to other monsoonal delta regions to enhance water supply.