Paddy cultivation is constrained due to shortage of rainfall or irrigation water supply. With the population
growth, farmers have to increase the paddy production to meet the existing as well as future demand
with the same or less land cultivated at the present. Wastewater from domestic and municipal sources
which are harmless and that can be harvested can be diverted to irrigate paddy fields thereby increasing
the extent of land under paddy. A study was conducted in selected Divisional secretariat divisions from
Puttalam District, Sri Lanka in order to explore the potential increment of land that can be brought
under paddy cultivation with the utilization of municipal and domestic wastewater. The wastewater
generation was estimated based on the population and water consumption data. The extent of paddy
land under minor irrigation and rainfed agriculture, potential asweddumized extent, land area cultivated
in Maha (main) season and Yala (off) season and the areas harvested were collected from district
agriculture department. It is noted that all the available lands were not cultivated and not harvested in
both Maha and Yala seasons. Lands left without any production is high in the Yala season compared to
the Maha season. Only a part of the land area is harvested from the total area sown. One of the major
reasons for crop failure is shortage of supplementary irrigation water, inadequate rainfall and irrigation
water. About 22% of the uncultivated lands in Maha can be brought under cultivation if 55% of the
gray water generated is collected and diverted to irrigate paddy fields. In Yala season, only very small
portion of uncultivated land (5% of uncultivated land) can be brought under cultivation with the gray
water irrigation.