1. Introduction

The Water Quality Monitoring and Controlling for Gray Water Recycling system is designed to monitor and improve the quality of wastewater from sources such as bathrooms, showers, and washbasins for potential reuse. By combining water quality sensors, a NodeMCU controller, and automated treatment components, the system supports efficient water recycling, reduces freshwater consumption, and promotes sustainable water management.

2. Objectives

• Monitor gray water quality in real time.

• Measure pH, turbidity, and water level.

• Automate the water treatment process.

• Control water flow based on measured quality.

• Reduce freshwater consumption.

• Support sustainable water reuse.

3. Methodology

• Collect gray water in a storage tank.

• Install sensors to monitor pH, turbidity, and water level.

• Use NodeMCU to process sensor readings.

• Activate a pump and relay-controlled treatment system when required.

• Filter the gray water using suitable filtration materials.

• Display water quality readings and system status through an IoT dashboard.

4. Instrument List

• NodeMCU ESP8266

• pH Sensor

• Turbidity Sensor

• Water Level Sensor

• Temperature Sensor

• Relay Module

• Water Pump

• Filtration Unit

• Solenoid Valve

• LCD Display

• Battery

• Water Storage Tank

5. Working Principle

• Gray water enters the collection tank.

• Sensors measure pH, turbidity, and other selected water quality parameters.

• NodeMCU processes the readings and compares them with predefined limits.

• The pump circulates water through the filtration unit for treatment.

• The controller manages water flow according to the programmed conditions.

• Water quality readings and treatment status are displayed through the IoT dashboard.

6. Advantages

• Real-time water quality monitoring

• Automated treatment control

• Reduced freshwater consumption

• Efficient water recycling

• Remote system monitoring

• Environmentally friendly operation

7. Conclusion

The Water Quality Monitoring and Controlling for Gray Water Recycling system demonstrates how IoT and automated treatment can support water conservation. By monitoring water quality and controlling filtration and flow, the system helps make gray water reuse more efficient. Before reuse, the treated water must meet the quality requirements for its intended application; it should not be assumed safe for drinking.