Presence of disinfection by-products (DBPs) in public drinking water and associated health risks, such as cancers are the contentious issues in the province of Newfoundland and Labrador (Canada). However, there is no large population level study showing any association between exposure to DBPs and water infrastructure and cancer risks. The objectives of the study were to explore any association between DBPs levels in public water supplies and cancer rates in individual communities and population of the communities. Community-based DBPs levels (trihalomethanes (THMs) and haloacetic acids (HAAs)) (2010-2016) were collected from the provincial government’s website. The gastrointestinal and genitourinary cancer data were obtained from the provincial cancer registry. Out of total 362,670 population (310 communities with 336 public drinking water supplies), 60,913 (17%) were considered exposed to DBP exceedances. Odds ratios for the rates of gastrointestinal and genitourinary, and combined cancer and THMs and HAAs exceedances (combined) were 1.31 (95%CI: 1.20-1.43), 1.21 (95%CI: 1.02-1.44) and 1.31 (95%CI: 1.21-1.42) respectively. However, HAAs exposure has a stronger association (than THMs) with gastrointestinal, genitourinary, and combined cancer. Of the 260 systems servicing small communities (<1000 residents), 44 experienced either THMs or HAAs exceedances, and 92 experienced both. Of the 53 systems servicing medium communities (1000-3999 residents), 13 experienced either THMs or HAAs exceedances, and 18 experienced both. In contrast, of the 23 systems servicing large communities (>4000 residents), 2 experienced HAA exceedances, and 3 experienced both. 61.40% of the 272 systems that rely on a surface water source some form of DBPs exceedance. While only 7.58% of the 66 systems that rely on a ground water source experienced any type of DBPs exceedance. Smaller communities with low revenues experienced more exceedances of DBPs and higher prevalence of related cancers.