Clean water provision still becomes a problem faced by developing countries, including Indonesia. One of the factors contributing to this problem is limited financial capability of the government. Therefore, if the government intend to increase clean water service coverage, they should be carefully choosing the most efficient strategy. This study tries to help the government of Bandung Regency in Indonesia to increase water service coverage by examining two different alternatives in provision of clean water service, which are small scale and large scale piped system. By employing Benefit Cost Analysis (BCA) this study found that despite the cost to develop large scale piped system is higher, the benefit gained from the system is significantly far exceeded the benefit of small system. As a result, the large system produces larger net benefit than the small one. The benefit of large scale piped system mainly contributed by illness incident and time saving for collecting water.