The cancer risks (CR) by oral ingestion, dermal absorption, and inhalation exposure of trihalomethanes (THM) from tap water of ten districts in Fortaleza, Brazil were estimated. The mean levels of THM compounds were obtained in Fortaleza tap water as follow: 63.9 μg L⁻¹ for chloroform (CHCl₃), 40.0 μg L⁻¹ for bromodichloromethane (CHBrCl₂), and 15.6 μg L⁻¹ for dibromochloromethane (CHBr₂Cl). Bromoform (CHBr₃) was not detected. The mean CR for THMs in tap water is 3.96 × 10⁻⁴. The results indicate that Fortaleza residents have a higher CR by inhalation than dermal absorption and oral ingestion. The CR for CHCl₃ contributes with 68% as compared with the total CR, followed by CHBrCl₂ (21%), and CHBr₂Cl (11%). The hazard index (HI) is about ten times lower than unity, not indicating non-cancer effects.