⚙️ The Smart Solution – IoT Water Monitoring System
🔁 J ourney of Building the System – Emotions + Technical Steps
1️⃣ Placing the Sensor on the Tank
2️⃣ Writing the Code
3️⃣ Blynk Mobile Dashboard
4️⃣ Auto Motor Control (Optional
📲 R eal-Life Experience – My Tank is Now Smart
🌍 W hy This Project Is So Important
💡 F inal Thoughts & Inspiration

Published November 4, 2025 © MIT

IoT Based Smart Water Level Monitoring System using ESP32

Smart IoT Water Level System using ESP32, Ultrasonic Sensor & Blynk. Real-time tank monitoring, alerts & motor control by Yarana IoT Guru.

BeginnerFull instructions provided8 hours185

IoT Based Smart Water Level Monitoring System using ESP32

Things used in this project

Software apps and online services

Arduino IDE

Story

It all started with a very common problem...

One early morning around 5 AM, water was overflowing from the overhead tank.The motor was left ON the whole night, and nobody noticed when the tank got full.

Water was wasted

Water was wasted

Electricity was wasted

Electricity was wasted

The motor was about to burn out due to overload

The motor was about to burn out due to overload

And the truth is—this is not just one household's problem.This happens every day in thousands of homes, hostels, apartments, and villages.

At that moment, I thought...

“We are building robots, drones, and AI technology…But we still don’t know when our water tank is full or empty?Isn’t that strange?”

“We are building robots, drones, and AI technology…But we still don’t know when our water tank is full or empty?Isn’t that strange?”

This is where the idea was born—to create a Smart IoT-Based Water Level Monitoring System that can:

✔ Show real-time water level on mobile✔ Send alerts when the tank is full or empty✔ Automatically turn the motor OFF to prevent overflow✔ Use Wi-Fi & IoT with ESP32 + Blynk App✔ Be affordable and DIY-friendly for everyone

⚙️ The Smart Solution – IoT Water Monitoring System

To turn this idea into reality, I chose:

ESP32 Board – Wi-Fi enabled microcontroller

ESP32 Board – Wi-Fi enabled microcontroller

HC-SR04 Ultrasonic Sensor – Measures tank water level without contact

HC-SR04 Ultrasonic Sensor – Measures tank water level without contact

Blynk IoT App – Displays data on a smartphone

Blynk IoT App – Displays data on a smartphone

Relay Module (optional) – Auto motor control

Relay Module (optional) – Auto motor control

Why this combination?✅ Low cost✅ Easy to build✅ Works wirelessly✅ Perfect for real homes and villages

🔁 J ourney of Building the System – Emotions + Technical Steps

1️⃣ Placing the Sensor on the Tank

The ultrasonic sensor was placed on top of the water tank, facing downwards to measure the distance to the water surface.

2️⃣ Writing the Code

The main logic was:Water Level = Tank Height – Measured DistanceThen send the value to the Blynk App every second.

3️⃣ Blynk Mobile Dashboard

A gauge shows exact water level in percentage or cm

A gauge shows exact water level in percentage or cm

If water level ≥ 95% → Notification: “Tank Full – Motor Turned OFF!”

If water level ≥ 95% → Notification: “Tank Full – Motor Turned OFF!”

If water level ≤ 10% → “Water Low – Please Turn ON Motor”

If water level ≤ 10% → “Water Low – Please Turn ON Motor”

4️⃣ Auto Motor Control (Optional)

Using a relay connected to ESP32, the motor turns OFF automatically when the tank is full.

📲 R eal-Life Experience – My Tank is Now Smart!

Whether I am at home or outside, I can:

✔ Check water level on my phone✔ Get notifications before overflow happens✔ Turn motor ON/OFF with just one click✔ Relax—no more climbing to the roof to check tank level

One of my neighbors saw it and said:“Bro, this is genius! No more water waste and no tension.”

And that moment felt amazing.

🌍 W hy This Project Is So Important?

Problem

Smart IoT Solution

Water overflows

Auto alert + motor OFF

Need to check tank manually

Live data on mobile

Motor burns due to overload

Automatic cutoff using relay

Water finishes unexpectedly

Low water alert on phone

Wasted time & energy

Fully automated system

💡 F inal Thoughts & Inspiration

“Technology isn’t just about big inventions.It’s about solving small problems of everyday life.This Smart Water Level Monitoring System is a step towards a smarter,efficient, and water-saving future.”

“Technology isn’t just about big inventions.It’s about solving small problems of everyday life.This Smart Water Level Monitoring System is a step towards a smarter,efficient, and water-saving future.”

Created with ❤️ by Yarana IoT Guru (Abhishek Maurya)

✅ 📌 Complete Code (with Comments) for ESP32 + Ultrasonic Sensor + Blynk

/************* Smart Water Level Monitoring System *************
   Hardware: ESP32, HC-SR04 Ultrasonic Sensor, Blynk App
   Features:
   ✔ Measure water level in tank
   ✔ Send percentage to Blynk App
   ✔ Show water level on Serial Monitor
   ✔ Automatically detect tank full or empty
   ✔ Motor control can be added easily
****************************************************************/

#define BLYNK_TEMPLATE_ID "Your_Template_ID"
#define BLYNK_TEMPLATE_NAME "Water Level Monitor"
#define BLYNK_AUTH_TOKEN "Your_Blynk_Auth_Token"

#include <WiFi.h>
#include <WiFiClient.h>
#include <BlynkSimpleEsp32.h>

// Wi-Fi Credentials
char ssid[] = "Your_WiFi_Name";
char pass[] = "Your_WiFi_Password";

// Ultrasonic Sensor Pins
#define TRIG_PIN  5
#define ECHO_PIN  18

// Tank Dimensions (in cm)
const int TANK_DEPTH = 100; // Tank height in centimeters

long duration;
float distance, waterLevel, waterPercent;

BlynkTimer timer;

/***************** Function to Measure Water Level *****************/
void measureWaterLevel() {
  // Send ultrasonic pulse
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Read echo time
  duration = pulseIn(ECHO_PIN, HIGH);

  // Calculate Distance (cm)
  distance = duration * 0.034 / 2;

  // Calculate water level
  waterLevel = TANK_DEPTH - distance;

  // Calculate percentage
  waterPercent = (waterLevel / TANK_DEPTH) * 100.0;

  if (waterPercent < 0) waterPercent = 0;
  if (waterPercent > 100) waterPercent = 100;

  // Send data to Blynk
  Blynk.virtualWrite(V0, waterPercent);  // Water Level in %
  Blynk.virtualWrite(V1, waterLevel);    // Water Level in cm

  // Print on Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.print(" cm | Water Level: ");
  Serial.print(waterLevel);
  Serial.print(" cm | Tank Filled: ");
  Serial.print(waterPercent);
  Serial.println(" %");
}

/***************** Setup Function *****************/
void setup() {
  Serial.begin(115200);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

  // Connect to Blynk
  Blynk.begin(BLYNK_AUTH_TOKEN, ssid, pass);

  // Timer runs every 1 second
  timer.setInterval(1000L, measureWaterLevel);
}

/***************** Main Loop *****************/
void loop() {
  Blynk.run();
  timer.run();
}