IoT Based Manhole Detection & Monitoring

Abstract

Urban drainage systems face frequent hazards such as manhole overflow, toxic gas accumulation, and unauthorized lid opening, which may lead to accidents and health risks. Conventional manual inspection is inefficient and unsafe. This paper presents an IoT-based smart manhole monitoring system employing a master–slave architecture using ESP32 and Arduino Nano controllers. Wireless communication between nodes is achieved through NRF modules, while GSM provides emergency alert messaging. Multiple sensors including float, tilt, gas (MQ-2), and temperature (DHT11) are utilized for real-time environmental monitoring. RTC modules enable low-power operation through scheduled sleep cycles and event-based wake-up.A novel hollow manhole cover design is introduced, where all electronics are protected inside the cover while sensors remain externally exposed for accurate detection. Instead of GPS, predefined coordinates are assigned to each manhole to reduce power consumption and system cost. The system supports emergency-triggered communication even during sleep mode, ensuring immediate alert transmission. The proposed design enhances public safety, reduces manual inspection, and offers a scalable and cost-effective solution for smart city infrastructure.

Introduction

Rapid urbanization has increased the burden on sewage systems, making manual manhole inspection unsafe due to toxic gases, overflow, and poor ventilation, while open or displaced covers pose serious public hazards. Existing monitoring methods are inefficient, lack real-time response, and often fail to ensure worker and pedestrian safety.

The proposed solution is an IoT-based smart manhole monitoring system using a master–slave architecture, where an ESP32 master node communicates with Arduino Nano slave nodes via NRF wireless modules. The system uses multiple sensors (water level, gas, temperature, and tilt) to detect hazardous conditions, with a hollow manhole cover design protecting internal electronics while allowing accurate external sensing. GSM technology enables real-time alert messages to authorities during emergencies.

Key innovations include low-power operation with sleep modes, emergency wake-up via tilt detection, secure hardware placement, and distributed monitoring through wireless nodes. The system improves safety, reduces manual inspection, enhances response time, and provides a cost-effective, scalable solution for smart city sewage infrastructure management.

Conclusion

The proposed smart manhole monitoring system presents an efficient and reliable solution for enhancing urban sewage management and public safety. By integrating multiple sensors for detecting water level, temperature, toxic gas concentration, and manhole cover displacement, the system enables continuous and automated monitoring of underground manholes. The use of hollow and lockable manhole covers protects the main circuitry while allowing sensors to directly interact with the environment, improving durability and sensing accuracy. The master–slave architecture using Arduino Nano slave nodes and an ESP32 WROOM-32 master ensures scalable monitoring of multiple manholes. Wireless communication through NRF modules allows rapid data transfer, while GSM-based alerting provides immediate notification to municipal authorities during hazardous conditions. The emergency wake-up mechanism triggered by tilt or abnormal sensor readings further enhances system responsiveness. Low-power operation achieved through RTC-based sleep cycles significantly reduces energy consumption, making the system suitable for long-term outdoor deployment. Overall, the proposed system minimizes manual inspection, improves worker safety, and enables proactive sewage maintenance. By combining low-power IoT technology, wireless communication, and intelligent alerting, this project demonstrates a practical and scalable approach toward safer, cleaner, and smarter urban infrastructure management.

References

The proposed smart manhole monitoring system presents an efficient and reliable solution for enhancing urban sewage management and public safety. By integrating multiple sensors for detecting water level, temperature, toxic gas concentration, and manhole cover displacement, the system enables continuous and automated monitoring of underground manholes. The use of hollow and lockable manhole covers protects the main circuitry while allowing sensors to directly interact with the environment, improving durability and sensing accuracy. The master–slave architecture using Arduino Nano slave nodes and an ESP32 WROOM-32 master ensures scalable monitoring of multiple manholes. Wireless communication through NRF modules allows rapid data transfer, while GSM-based alerting provides immediate notification to municipal authorities during hazardous conditions. The emergency wake-up mechanism triggered by tilt or abnormal sensor readings further enhances system responsiveness. Low-power operation achieved through RTC-based sleep cycles significantly reduces energy consumption, making the system suitable for long-term outdoor deployment. Overall, the proposed system minimizes manual inspection, improves worker safety, and enables proactive sewage maintenance. By combining low-power IoT technology, wireless communication, and intelligent alerting, this project demonstrates a practical and scalable approach toward safer, cleaner, and smarter urban infrastructure management.

Copyright

Copyright © 2026 Prof. R.V. Nilajagi, Mrudul Matade, Arya Manolkar, Atharva Band, Suraj Survase. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.