Sri Lanka is the second worst affected Country in tsunami disaster in year 2004. It was the greatest natural devastation in the history. It damaged 87% of the coastal belt of the country. It destroyed existing water Supply and sanitation systems disrupting the public services. After the tsunami there was an urgent need for temporary water supply and sanitation facilities for internally displaced persons lived in temporary camps. Within few weeks, it was necessary to provide water and sanitation facilities to transitional camps. This situation lasted for few months. Then, it was a challenge to provide water and sanitation facilities to resettlement sites. The situation was addressed with the help of governmental and non-governmental organizations. This paper illustrates the challenges faced in providing water and sanitation facilities in various phases in detail. It also emphasis on the need of an emergency preparedness plans in order to face similar Situations in future.