In Borno State, groundwater serves as the predominant source of fresh water for daily
consumption. However, concerns persistence about its quality due to escalating radon
concentrations resulting from mining activities. This research work assesses the long time
dose which result from exposure to radon through the intake of groundwater in Borno State
University (BOSU) Campus and Njimtilo students’ residential area, Maiduguri metropolis,
Borno, utilizing a liquid scintillation counter. Thirty (30) water samples from borehole
were collected, which reveals the average radon concentration of 18.1219 Bq/L in BOSU
Campus and Njimtilo. The annual mean ingestion/inhalation effective doses were 6.3 ×
10−2 mSv/y and 4.6×10−2mSv/y, respectively. In BOSU Campus and Njimtilo, the
average extra lifetime cancer risk for ingestion was 0.222 × 10−3, and for inhalation, it
was 0.16 ×10−3. The average radon concentration in the research area exceeded the SON
and USEPA standard of 11.1 Bq/L. Despite this, based on the findings of this work, the
radon concentration is deemed acceptable, allowing residents to continue with the use of
water in the area pending when preventive measures are implemented. Nonetheless,
ongoing assessment in the area is advisable to mitigate potential cancer risks. To cover the
zone entirely, further investigations should explore more sources within the area in
question. Given the temporal variation in radon concentrations due to rainfall dilution,
regular testing and adherence to regional guidelines are recommended to address and
alleviate potential health risks.