Groundwater contamination is a major environmental concern that impacts both irrigation
and drinking water supplies. To evaluate the water quality in Thakurganj block, Kishanganj
district, Bihar, for its suitability for drinking and irrigation, a total of 55 groundwater samples
(1000 mL each) were collected using GPS-based methods between April and May 2022. The
samples were stored in plastic bottles at 4°C for laboratory analysis of their physicochemical
properties. Standard methodologies were used for analysis, and the results were assessed
based on the guidelines of WHO, APHA, and USDA for drinking and irrigation purposes.
Many groundwater samples from the Thakurganj block were found unsuitable for drinking
due to high iron contamination, exceeding the permissible limit. However, the groundwater
was classified under the C1S1 category for irrigation, indicating it is suitable for crop
production.