Arduino UNO Smart Water Quality Monitoring System | pH, Turbidity, TDS Sensor

💧 Environmental Monitoring 🔬 3 Sensors ⚙️ Arduino UNO 📡 IoT Ready

Smart Water Quality
Monitoring System

Measure pH, turbidity, and TDS (Total Dissolved Solids) in real time using Arduino UNO. This advanced environmental monitoring project is ideal for drinking water testing, aquaculture, wastewater analysis, and IoT-based smart water management.

~15 min read 7 Components Arduino C++

🧪

pH Sensor

A1 (Analog)

pH 7.2

🌊

Turbidity

A2 (Analog)

312 NTU

⚗️

TDS Sensor

A0 (Analog)

248 ppm

0Requirements

Components Required

🔵

Arduino UNO

ATmega328P microcontroller

🧪

pH Sensor Module

Analog output → A1

🌊

Turbidity Sensor

Analog output → A2

⚗️

TDS Sensor

Analog output → A0

📟

16×2 LCD Display

4-bit mode (optional)

🔋

Power Supply

5V battery or USB

🔌

Jumper Wires

For all connections

🔬 Science

How the Monitoring System Works

Sensor 01

🧪 pH Sensor — Acidity / Alkalinity

Measures hydrogen ion concentration to determine whether water is acidic, neutral, or alkaline.

Analog pin A1

pH < 7 → Acidic water
pH = 7 → Neutral (pure water)
pH > 7 → Alkaline water
Drinking water: pH 6.5 – 8.5

Sensor 02

🌊 Turbidity — Water Clarity

Detects suspended particles using infrared light scattering. Higher turbidity = more contamination.

Analog pin A2

Measures in NTU (Nephelometric)
Clear water: < 1 NTU
Drinking limit: < 4 NTU (WHO)
High NTU signals contamination

Sensor 03

⚗️ TDS — Total Dissolved Solids

Measures concentration of dissolved minerals, salts, and metals — indicates overall water purity.

Analog pin A0

Measures in ppm (mg/L)
Excellent: < 300 ppm
Acceptable: 300 – 600 ppm
Poor quality: > 900 ppm

pH Scale Reference

01234 56789 1011121314

🔴 Acidic

pH 0 – 6.9

🟢 Neutral

pH 7.0

🔵 Alkaline

pH 7.1 – 14

1Wiring

Circuit Connections

Component	Pin/Terminal	Arduino Pin	Wire
TDS Sensor	VCC	5V	Red
	GND	GND	Black
	AOUT	A0	Orange
pH Sensor	VCC	5V	Red
	GND	GND	Black
	AOUT	A1	Yellow
Turbidity Sensor	VCC	5V	Red
	GND	GND	Black
	AOUT	A2	Green
16×2 LCD (4-bit)	VCC / VSS	5V / GND	/
	RS / E / R/W	D12 / D11 / GND	Blue
	D4–D7	D10 / D9 / D8 / D7	Purple

All three sensor modules output a 0–5V analog signal proportional to their respective measurements. The Arduino's built-in 10-bit ADC converts these to values ranging from 0–1023.

2Wokwi Config

diagram.json

Paste this into Wokwi's diagram.json tab. Three potentiometers simulate the sensor analog outputs — turn each to change readings.

diagram.json

{
  "version": 1,
  "author": "Arduino Water Quality Monitor",
  "editor": "wokwi",
  "parts": [
    {
      "type": "wokwi-arduino-uno", "id": "uno",
      "top": 0, "left": 0, "attrs": {}
    },
    {
      "type": "wokwi-potentiometer", "id": "tds_pot",
      "top": -120, "left": -200,
      "attrs": { "label": "TDS Sensor (A0)" }
    },
    {
      "type": "wokwi-potentiometer", "id": "ph_pot",
      "top": -120, "left": 0,
      "attrs": { "label": "pH Sensor (A1)" }
    },
    {
      "type": "wokwi-potentiometer", "id": "turb_pot",
      "top": -120, "left": 200,
      "attrs": { "label": "Turbidity (A2)" }
    },
    {
      "type": "wokwi-lcd1602", "id": "lcd1",
      "top": 200, "left": 200, "attrs": {}
    }
  ],
  "connections": [
    // TDS sensor (potentiometer) → A0
    [ "tds_pot:VCC", "uno:5V",   "red",    [ "v0" ] ],
    [ "tds_pot:GND", "uno:GND.1", "black",  [ "v0" ] ],
    [ "tds_pot:SIG", "uno:A0",   "orange", [ "v0" ] ],

    // pH sensor (potentiometer) → A1
    [ "ph_pot:VCC",  "uno:5V",   "red",    [ "v0" ] ],
    [ "ph_pot:GND",  "uno:GND.1", "black",  [ "v0" ] ],
    [ "ph_pot:SIG",  "uno:A1",   "yellow", [ "v0" ] ],

    // Turbidity sensor (potentiometer) → A2
    [ "turb_pot:VCC", "uno:5V",   "red",    [ "v0" ] ],
    [ "turb_pot:GND", "uno:GND.1", "black",  [ "v0" ] ],
    [ "turb_pot:SIG", "uno:A2",   "green",  [ "v0" ] ],

    // LCD (4-bit mode)
    [ "lcd1:VSS", "uno:GND.2", "black",  [ "v0" ] ],
    [ "lcd1:VDD", "uno:5V",    "red",    [ "v0" ] ],
    [ "lcd1:V0",  "uno:GND.2", "black",  [ "v0" ] ],
    [ "lcd1:RS",  "uno:12",   "blue",   [ "v0" ] ],
    [ "lcd1:RW",  "uno:GND.2", "black",  [ "v0" ] ],
    [ "lcd1:E",   "uno:11",   "blue",   [ "v0" ] ],
    [ "lcd1:D4",  "uno:10",   "purple", [ "v0" ] ],
    [ "lcd1:D5",  "uno:9",    "purple", [ "v0" ] ],
    [ "lcd1:D6",  "uno:8",    "purple", [ "v0" ] ],
    [ "lcd1:D7",  "uno:7",    "purple", [ "v0" ] ],
    [ "lcd1:A",   "uno:5V",   "red",    [ "v0" ] ],
    [ "lcd1:K",   "uno:GND.2", "black",  [ "v0" ] ]
  ],
  "dependencies": {}
}

3Code

Arduino Code

The code reads all three sensors every second and outputs formatted readings to the Serial Monitor. Extend it with the LCD library to show values on the 16×2 display.

sketch.ino — Arduino C++

/*
 * Arduino UNO Smart Water Quality Monitoring System
 * Sensors: TDS (A0), pH (A1), Turbidity (A2)
 * Output: Serial Monitor + 16x2 LCD
 * Use potentiometers in Wokwi to simulate sensor values
 */

// ── PIN DEFINITIONS ───────────────────────────────────────────
const int tdsPin       = A0;   // TDS sensor analog output
const int phPin        = A1;   // pH sensor analog output
const int turbidityPin = A2;   // Turbidity sensor analog output

// ── CALIBRATION CONSTANTS ─────────────────────────────────────
// These map 0–1023 ADC range to real-world units.
// Adjust these values for your specific sensor modules.
const float TDS_FACTOR  = 0.5;    // ppm per ADC unit (approx)
const float PH_OFFSET   = 14.0;   // pH 0–14 mapping offset
const float TURB_FACTOR = 1.0;    // NTU per ADC unit (approx)

void setup() {
  Serial.begin(9600);
  pinMode(tdsPin,       INPUT);
  pinMode(phPin,        INPUT);
  pinMode(turbidityPin, INPUT);

  Serial.println("========================================");
  Serial.println("  Smart Water Quality Monitoring System");
  Serial.println("  Sensors: TDS | pH | Turbidity");
  Serial.println("========================================");
  Serial.println();
}

void loop() {
  // Read raw ADC values (0–1023)
  int tdsRaw       = analogRead(tdsPin);
  int phRaw        = analogRead(phPin);
  int turbidityRaw = analogRead(turbidityPin);

  // Convert to real-world values
  float tdsValue       = tdsRaw * TDS_FACTOR;
  float phValue        = (phRaw / 1023.0) * PH_OFFSET;
  float turbidityValue = turbidityRaw * TURB_FACTOR;

  // Determine water quality labels
  String phStatus  = (phValue < 6.5) ? "ACIDIC" :
                     (phValue > 8.5) ? "ALKALINE" : "NORMAL";
  String tdsStatus = (tdsValue < 300) ? "EXCELLENT" :
                     (tdsValue < 600) ? "GOOD" :
                     (tdsValue < 900) ? "ACCEPTABLE" : "POOR";

  // Print formatted output to Serial Monitor
  Serial.println("──────────────────────────────────────");
  Serial.print("TDS Value:      "); Serial.print(tdsRaw);
  Serial.print(" raw  →  "); Serial.print(tdsValue, 1);
  Serial.print(" ppm  ["); Serial.print(tdsStatus); Serial.println("]");

  Serial.print("pH Value:       "); Serial.print(phRaw);
  Serial.print(" raw  →  pH "); Serial.print(phValue, 2);
  Serial.print("  ["); Serial.print(phStatus); Serial.println("]");

  Serial.print("Turbidity:      "); Serial.print(turbidityRaw);
  Serial.print(" raw  →  "); Serial.print(turbidityValue, 1);
  Serial.println(" NTU");

  Serial.println();
  delay(1000);   // Read every 1 second
}

/* ── SERIAL MONITOR OUTPUT EXAMPLE ──────────────────────────────
   ========================================
     Smart Water Quality Monitoring System
     Sensors: TDS | pH | Turbidity
   ========================================

   ──────────────────────────────────────
   TDS Value:      512 raw  →  256.0 ppm  [EXCELLENT]
   pH Value:       372 raw  →  pH 7.23  [NORMAL]
   Turbidity:      290 raw  →  290.0 NTU

   ──────────────────────────────────────
   ...
*/

✨ Features

Key Features

Arduino UNO environmental monitoring

Real-time pH level measurement

Turbidity detection for water clarity

TDS dissolved solids monitoring

16×2 LCD live data display

Analog sensor interfacing (3 channels)

Serial Monitor formatted logging

Water quality status labels (GOOD/POOR)

Portable battery-powered design

Expandable to IoT cloud monitoring

Calibration constants for accuracy

Wokwi simulation with potentiometers

🌍 Use Cases

Applications

🚰 Drinking water quality testing

🌊 River & lake pollution monitoring

🐟 Aquaculture water management

🌾 Smart irrigation systems

🏭 Industrial wastewater analysis

🔬 Environmental research projects

🏙️ IoT smart water management

🎓 Engineering final year projects

🏫 Science exhibition models

🧬 Research lab water studies

🏊 Swimming pool monitoring

🌱 Hydroponic nutrient control

🚀 Extend It

Upgrade to IoT-Based Water Monitoring

This project can be expanded into a fully connected cloud-based monitoring solution suitable for smart cities, industrial automation, and agricultural management.

📶

ESP8266

Add WiFi connectivity for remote monitoring

⚡

ESP32

Advanced IoT integration + Bluetooth

☁️

Cloud Platform

ThingSpeak, Blynk, or Firebase logging

📱

Mobile Dashboard

Real-time data on any smartphone

📡

GSM Module

SMS alerts when quality thresholds exceeded

With ESP8266 or ESP32 integration, the system becomes a real-time cloud-based water quality monitoring solution deployable for smart cities and precision agriculture.

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Arduino UNO Smart Water Quality Monitoring System Using pH and Turbidity Sensor | IoT Water Testing Project

Smart Water Quality
Monitoring System

Components Required

How the Monitoring System Works

Circuit Connections

diagram.json

Arduino Code

Key Features

Applications

Upgrade to IoT-Based Water Monitoring

More Projects by Category

Comments

Post a Comment

try for free

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Arduino UNO Smart Water Quality Monitoring System Using pH and Turbidity Sensor | IoT Water Testing Project

Smart Water QualityMonitoring System

Components Required

How the Monitoring System Works

Circuit Connections

diagram.json

Arduino Code

Key Features

Applications

Upgrade to IoT-Based Water Monitoring

More Projects by Category

Comments

Post a Comment

try for free

Best 15 IoT Projects Using ESP32 for Beginners & Advanced Makers in 2026

BEST 25 ARDUINO WOKWI SIMULATOR PROJECTS

Top 20 Raspberry Pi Projects for Beginners - Complete Guide 2026

Intermediate Projects (Build Your Skills)

Advanced Projects (Master Level)

Smart Water Quality
Monitoring System