Introduction: Water Level Indicator With Alarm

Picture of Water Level Indicator With Alarm
Today I am going to talk about a very useful project that I had taken up. It is called the Water Level Indicator. Nowadays everybody has overhead tank at their homes. But everyone who has a water tank above knows the kind of problems that they face. Firstly there is no system to track the water in the tank. Then there come a secondary problem that is when their water pump is started they have no idea when it gets filled up and sometimes there are situation where the pump keeps on pumping water to the tank and the water starts spilling out from the tank. There is wastage of energy as well as wastage of water.

Step 1: Things You Need...

Picture of Things You Need...

4 - bc548

6 - 220 ohm resistors

3 - colour led

1 - buzzer

1 - 9v battery + battery clip

Step 2: Circuit Diagram

Picture of Circuit Diagram

The circuit consisting of 5 sensing probes which is dipped in water to sense the level of water. The probe A is connected as common to other four , which should be at the bottom most part of the water tank, also it act as a reference level. The probes B, C, D and E are set as minimum, minimum+ , middle and maximum level respectively.

Assemble the circuit...... 

Step 3: FINISH.. :)

Picture of FINISH..  :)
When water in the tank touches the probe A and B both, a small current flows from A to B through water and to the base of transistor T1 via a 220KΩ resistor. As a result the transistor conducts causing the LED1 to glow. Similarly, when water touches sensor C, LED2 glow and indicates that WATER is at minimum+ and when water touches sensor D , LED 3  glow and indicates that WATER is at. MIDDLE . Finally, when the water touches sensor E ,  BUZZER turns on and indicates the tank is completely filled.


Biscuitus (author)2014-06-23

This is exactly the circuit I was looking for but battery wouldn't work for me as it's in a machine shop and we have too much going on to keep track of it and I don't feel like making a low voltage circuit, but I do have a 5v 1A wall wart, and all my math says I can do it, albeit my LED's may be dim...thoughts?

Also, very nice instructable, but maybe you could put the specs of some of the things you used (i.e. wattage of resistors, speaker specs etc.)? I know that for this circuit you could easily use a 1/8w resistor but the speaker I just kind of hummed a few bars and faked it and used a 1.5v speaker and put an LED in front of it to step the voltage down a touch.

Er Varun Goyal (author)Biscuitus2014-06-24

use a battery adapter in the place of a battery , soo that it reduce the cost and save your time also .

Biscuitus (author)Er Varun Goyal2014-06-24

I'm going to use a voltage divider and knock it down some. I lose a little in heat but it's for a Wire EDM water tank that I'm constantly over filling (and that wreaks havoc with the accuracy) so it'll get some cooling. Thanks for the response!

Er Varun Goyal (author)Biscuitus2014-06-24

thankyou sir , for your positive feedback .

maybe you can by modify the above circuit accourding to your requirement . :)

zsoltinyo (author)2014-02-13

Does this work with motor oil?

Biscuitus (author)zsoltinyo2014-06-23

If it works with motor oil you have much bigger problems than oil level :)

Er Varun Goyal (author)zsoltinyo2014-02-13

no sir , Engine oil does not conduct electricity
because there are no charge carriers in it.

highwind001 (author)2013-12-26

This can prove useful in my boat. Thank you much for posting

anytime buddy.. :) and thankyou

Royke (author)2017-07-03

Made something like this only difference I put the alarm on empty with a pnp- instead of a npn-transitor

Muhammad WaqasK (author)2016-08-30

mean agar tank 3rd floor pay ho toa wire almost 40 to 50 feet ban jaye gi? kya yeh circuit itne wire pay support kr sake ga, ore kya hum 12v ka adopter use kr sakte hai circuit mai kuch changing kr k?? reply me soon, i need to make this to save water and electricity

vapory made it! (author)2016-04-18


Please check my wireless water level indicator on my website

No external power supply to transmitter.(Two AA battery cells)

AhmedI26 made it! (author)2015-12-26

good work

sidnet03 (author)2015-12-04

I am a novice and am trying out such simple circuits. 1 question - why does this circuit need a transistor? Can we not just use resistor & LED and avoid transistor?

tevake (author)2015-11-13

Hi Dude! Thanks for your instructable! But...I need to be able to tell water level in my catamaran's multible water tanks, and I suspect that, because the water is shoshing around inside, that the circuits would be closed inadvertently? So, no go for my situation??? thanks for any suggestions..Summary: if water level is not constant, level cannot be reliably read out, right?

vsaini5 (author)2015-10-09

great work I am also going to make it... but can I use a 12v dc adapter or a mobile charger???

chintans (author)2015-07-29

I'm surprised.

I made this on breadboard with 2n2222 and that works but I'm wondering why the leds are blinking?
And a question, I'm using 5V 1A wall adaptor, what register I should use?

chintans (author)2015-07-28

I'm surprised.

I made this on breadboard with 2n2222 and that works but I'm wondering why the leds are blinking?
And a question, I'm using 5V 1A wall adaptor, what register I should use?

SrinivasV1 (author)2015-06-10

SadafS (author)2015-03-21


SadafS (author)2015-03-21


aqsas (author)2015-02-15

sir i wants to know that when tank overflows & circuitt is in on position and at the same time when someone uses tap water below, then is there chances of shock

ahmadbidai (author)2015-01-28


I'm working on a similar project of this type, but in my own case, i'm using a microcontroller and it's failed me at different trials. Perhaps i'm getting the connections wrong or something. I'd appreciate if you could help with the procedures.

Thank you!

sohailkhan246 (author)2015-01-06

My water tank is at 2nd floor, will the circuit work at ground floor

sfranch made it! (author)2014-12-29

Thanks Boss!!

depauw (author)2014-10-21


This seems te be exactly what i need, but for me it has to work the other way around.

I like to ge signal when the water in my tank is running low, and not when it reaches a high level. Is this possible?

Note that I'm not a genius in electricity, I'm a Pharmacist :-)

Kind regards

mahesh.pagda (author)2014-09-06

why we can use inwater level indctior in use 220 ohms rasitance? we also use 260 ya 200 ohms rasitance

mahesh.pagda (author)2014-09-06

why we can use inwater level indctior in use 220 ohms rasitance? we also use 260 ya 200 ohms rasitance

Shariffs (author)2014-08-27

Can i connect the Relay to the o/p of the low and high indication level, so that i can control the motor also. need suggestion please.

veerkumar.rathore (author)2014-08-25

where we have to connect the terminals of buzzer??

connect the buzzer on the wire highlited in the pic (PFA ) in series. please check the positive and negative wires. you have to connect the postive wire with the positive terminal wire of the battery and the negative one with the negative terminal wire of the battery .

sylvain01 (author)2014-08-23

thank you it's good for my sump pump and my hot-water tank

if my English is not good its

Er Varun Goyal (author)sylvain012014-08-25

any time sir :)

DWjemar123 (author)2014-08-23

wattage of the resistor?

swamy201 (author)2014-08-08

and also by using with relay and motor, the motor is automatically start when the tank is empty and stop when the tank is fully....if you know this is one please explain...........

swamy201 (author)2014-08-08

also by using motor and relays the motor is automatically start when the water is empty and stop when the water is full....if you know this is one please explain..because this project im using as a mini project

swamy201 (author)2014-07-26

is this ckt working correct or not

Er Varun Goyal (author)swamy2012014-07-26

yes, the circuit above is working fine and is tested by me... please watch videos in the manual above or

click here to watch on youtube..

p mishra (author)2014-06-24

hey did u saw a vid of learn by watch and made it

Er Varun Goyal (author)p mishra2014-06-24

Yes, but maybe the circuit there is not correct.
In that circuit -ve pin of L.E.D. is connected to the +Ve pin of the battery and the circuit was not working correctly. So I Modify the circuit and made it better.
now it works fine...

compare both the circuits and find the difference , try to make both the circuit to find the better result of difference :)

shantanutelharkar (author)2014-02-09

In what configuration is the BJT used?? Can u please tell me a bit about how did u design this circuit?

Thanks a ton.

sir , the circuit is based on 4 transistor switches. Each transistor is switched on to drive the corresponding LED/buzzer , when its base is supplied with current through the water through the electrode probes. :)

Well, I got that. Your circuit works fantastic and is very simple. I am asking whether the BJTs are working in Active region or Reverse Active region? Because generally the collector is connected to positive terminal of battery.

samalert (author)2013-12-30

I was really expecting a video of project in action.

Er Varun Goyal (author)samalert2014-01-20

dude.. here is the video of project in action.

thankyou for your feedback :)

samalert (author)Er Varun Goyal2014-01-20

Dude i really wanted to hear the sound the buzzer produce. Cause i was thinking of implementing it in my house for some reasons. Thanks a ton for posting the video.

Er Varun Goyal (author)samalert2014-01-20


anytime bro. .. and thanx to you too .

Er Varun Goyal (author)samalert2013-12-31

sorry frnd...
next time jb bhi bnaunga ... video post krunga .

btw project ki pic se b pta lga rha h k iski working kya h....

Er Varun Goyal (author)2014-01-20

updated.. with video of project in action. :)

About This Instructable




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