A study was carried out to estimate the gross alpha and beta radionuclide activity in groundwater sources within Mubi North metropolis, Adamawa State. Five water samples were collected from residential areas and analyzed using the Protean Instrument Corporation (PIC) MPC 2000DP, a single-channel proportional counter. The results for gross alpha radioactivity across the five locations were 0.066 ± 0.026, 0.0098 ± 0.014, 0.059 ± 0.025, 0.182 ± 0.040, and 0.049 ± 0.023 Bq/L, while gross beta radioactivity levels were 4.374 ± 1.19, 7.791 ± 1.21, 10.21 ± 1.23, 1.564 ± 1.17, and 0.654 ± 1.16 Bq/L for Shagari Locust borehole near Jumma’a mosque, Wurogude behind river borehole, ADSU Faculty of Management tap water, Lokuwa borehole near the Emir’s palace, and Federal Polytechnic Mubi water reservoir, respectively. The findings revealed that Lokuwa borehole recorded the highest gross alpha activity, while ADSU Faculty of Management tap water had the highest gross beta activity. Most of the sample locations exceeded the World Health Organization’s (WHO), recommended alpha activity limit of 0.5 Bq/L, with only the Federal Polytechnic Mubi reservoir showing gross beta levels below the WHO guideline of 1.0 Bq/L. This indicates that, with the exception of the Federal Polytechnic Mubi reservoir, the other groundwater sources may not be suitable for drinking. Additionally, three radiological parameters were calculated: the annual effective dose equivalent (AEDE), the annual gonadal dose equivalent (AGDE), and the excess lifetime cancer risk (ELCR). ELCR estimates the likelihood of developing cancer over an average lifespan of 70 years due to radiation exposure. The computed results were AEDE (? and ?): 0.0749/12.024 mSv/y, AGDE (? and ?): 0.1873/60.14 mSv/y, and ELCR (? and ?): 0.000262/0.042, respectively. The study concluded that the levels of gross alpha and beta activity in the water sources were significantly below the 100 Bq/L safety limits set by the International Commission on Radiological Protection (ICRP) and WHO for drinking water. Therefore, the radiation levels in these groundwater sources are unlikely to pose significant health risks to the local population.