Compact IoT-Enabled Water Testing Kit for E.coli and Coliform Contamination

Access to clean drinking water is essential, yet detecting E. coli and total coliform levels remains a challenge in rural communities. Many existing testing kits are primarily designed for laboratory use, are expensive, and require a long processing time, making them not easily accessible in rural areas. This paper presents a cost-effective, portable IoT-based dip test kit for detecting E. coli and total coliform levels in drinking water, following Bureau of Indian Standards (BIS) 10500:2012 guidelines. The system utilizes a colorimetric test strip, which changes colour when dipped in water. A TCS3200 colour sensor detects Red, Green, Blue (RGB) frequencies to identify light, pale, normal, and medium pink shades, indicating contamination levels. An ESP-32 microcontroller processes the data to determine E. coli presence and provide precise contamination measurements. When tested with water samples containing known E.coli concentrations, the device effectively differentiates contaminated and uncontam-inated samples while also providing E. coli concentration levels. It can serve as a reliable solution for on-site water screening, detecting E. coli within a concentration range of 200 to 2 ×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup>CFU/mL. Designed in a compact, pen-like form, this portable and easy-to-use system provides a reliable, low-maintenance water quality monitoring solution with extended battery life.