Nowadays water tank overflow is a big problem throughout the world that leads to wastage of water. Engineers have made a lot of solutions like ball valves which automatically stop the water flow once the tank gets full. But if you are an electronics engineer you should be able to make it completely automatic.
So here is a simple smart project water level indicator that will recognize the water level and will raise an alarm when the water tank full or any level, you can adjust it your own as well.

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Water level indicator
Water level indicator build in few steps

The Water Level Indicator has simple and easy steps to understand it’s a mechanism which benefits to identify and indicate the different water levels in the water tank or any other water container, it can be used for any purpose. This device works on the principle of sensing and it can be done by using a set of four probes that are placed at nine different levels in our container or tank.

The water level indicator has a simple and unique circuit that helps to detect easily and also indicates the water level in the tank or any other water container. Anyone can easily understand it as it’s easy to be made at the low cost of almost 1$.

Sensing is done by the four probs which can be seen in circuit diagram that is placed at four different levels on the tank walls or any container which wanted to be detected [ the probe- 4 to probe-1 are placed in rising order of height, 1 probe is common probe (which is supply carrying probe) is placed at the bottom of the container].

Principles of Water Level Indicator :
The principles of a water level indicator are actually very easy and uncomplicated. Water level indicators work with the help of sensor probes know as wires to indicate water levels in a storage tank or any container. These wires send information to the led light which glows and when the container or water tank gets full an alarm or indicator is turned on.

How does the Water Level Indicator works?
The circuit is intended to show four-level of water stored in the tank. That is low-level, medium, half, and full but not overflowing. It can also be set according to your own algorithms.
When the water tank is empty a red Led will glow. When water level increases and reaches the Medium level, the contact wires get shorted as water acts as a conducting medium between wire 1 and wire 2.
Green LED starts to glow as it depends on which led is connected with the water tank.
When the water level proceeds to increase and restores half of the tank or container, another wire of led will gets into contact with water and receives a small voltage from the connected battery.
As a result, the Yellow LED will glow.

When the water in the tank increases to a full tank, another green level LED will turn on.
The Red LED glows and also a buzzer is active which indicates that the tank is full and the water pump or motor should be OFF which leads us to control the wastage of water. The buzzer can also be connected to a low level as well. It depends upon the criteria and the requirements.

Circuit Diagram:-

The circuit diagram for the water level indicator is given below.

Circuit diagram
Circuit diagram

Components Required For Water Level Indicator Device :

Components list is given below, make sure that the resister value depends upon the supply if you are using 6v or 7v or 9v you can change the resister value because the resister glow will increases. As in my case, I have used 12v battery that’s why the output is 1k if your supply is less, then you may use 500ohms or 600ohms check which suits your requirements.

  • Resisters 1k
  • Buzzer
  • Switch
  • Jumper wires
  • Container
  • Battery 12v or less it depends read above carefully.
  • Connector

Step by step procedure to make the Water level indicator :

The step by step procedure is as follows.

Step 1:-

At first, arrange components according to the list above. The buzzer will sound when water tanks full.

Water level indicator

Any color of LEDs can be used. LED colors are not specified.

For LEDs Configuration, You can visit this

Water level indicator
LED’s of Different color

Switches are of different types any of them can be used but to avoid confusion in wiring or soldering this one will be the right option( given below).

Water level indicator
The switch used to on and Off  the circuit
level indicator
Scaling and measurements for LEDs

Step 2:-

Now place all the components in the desired places. Make sure to cut each part according to the components so that they cant be loosely bound.

Waterr level indicator circuit
Placing components

Then attach the buzzer with the glue or any other thing that can help you.

lever indicator without IC

Any type of connector can be used. The water level indicator without a connector is also possible as it works the same. Just simple changes in the circuit diagram are needed.

Battery level indicator

Step 3:-

Connect and bend all the negative wires as shown.

Connect negative wires of LED with negative Wire of another LED as shown in the figure below.

Battery level indicator
Attaching pins

This figure clearly shows the negative and positive pin of the LEDs.

Water level indicator
All pins attached

Step 4:-

Connect the Black pin of the buzzer to the negative pins of Led as shown below.

level indicater
Buzzer Black wire

Then cut all the pins of the led for soldering make sure that the black wire is attached with the negative(small pin of Led).

Level indicator
Cutting the resister pins

Step 5:-

Now connect Resisters to each Led to overcome the current.

A low-value resister may lead LED to be fused so precaution should be taken before using any resister.

Water level
Connecting resisters

Then connect the Red wire of the buzzer to the Red LED as shown in the figure below which will indicate that the tank is full as it will raise its volume.

Level indicator
Buzzer wire

Connect one wire of the Connector to the negative wire of the LEDs.

Connector wiring

Now another wire of the Connector is to be attached with the switch as shown below.

Connector second wire

Then connect the other leg of the blue LED with a resistor and switch as shown below. Make sure that the negative Pin should be attached with Negative pins of all Led as previously explained.

Blue Led connection

Last step:-

Make sure to follow all the steps for making a Water level indicator then it will work fine without any problem.

Making this project working with the steps is very important.

In the end, take a black wire and connect it with the switch and put it at the bottom of the container as this wire decides the current flow in the circuit of the water level indicator.

Black wire from Switch

Then connect all the wires (probes) to the resister as these probes will decide the level of the water tank.

water level indicator sensor
Connecting Wires to Resister

The connection should be done according to the figure below.

working of water level indicator using transistor bc547
Each wire should be connected accordingly

Close the box with care and connect all the wires to the level of the tank as each wire gives a different level signals.

water level indicator
Closing the box

Connect the supply as shown in the figure below.

power supply
Connecting supply

Test the circuit and it will work exactly according to our criteria.


It’s done. Now you don’t need to check your water tank level this device will do it’s work and will decrease your chores.