The study on the application into Drinking Water Region Company (PDAM) water reservoir to decrease of Ae. aegypti larvae population was conducted in Roviga Tondo and Palupi, palu Manicipality, from june to November 2005. Roviga Tondo as treatment area was given temephos to the community. Larvae survei on one week and four week after application showed that dosage of 5kgs temephos into drinking water region company (PDAM) reservoir could give a significant influence to larvae index decreased (p-value<0.05). In rogiva Tondo, Ae. aegypti showed significant preference to put eggs inside tyhe house rather than outside, whereas it was not significant in BTN Palupi.