I have a battery and a 5V active buzzer. Putting the end of circuits (just raw wire) in the bucket full of the tap water is not completing the circuit. The buzzer, battery, and circuit are fine since when I just connect the battery and buzzer, it gets completed, and the buzzer starts buzzing.

Components used

Wire: 0.55mm copper wire
Battery: 3 x SR44 1.55V 190mAh = ~4.5V
Buzzer: 5V Active Buzzer

I have a use of this project. I have to check if water is coming out of another end of pipe. I also tried to put the wires at the end of a pipe when water was flowing through, and the circuit was not complete.

For picturing the circuit/components (I hope it can give the idea) imagination

I am not sure here. Should I change the wires or increase the battery (by adding a few more SR44 cell)?

I am just a hobbyist and do not know many peculiar details. I would need your help to get this circuit working when water flows. Thanks.

  • 2
    \$\begingroup\$ The conductivity of water varies a lot based on its salt content. It might be too high resistance for your buzzer to buzz. \$\endgroup\$
    – Hearth
    Jul 24, 2021 at 4:07
  • \$\begingroup\$ As in add some salt to your water. And give it a stir to dissolve it. \$\endgroup\$ Jul 24, 2021 at 6:42
  • \$\begingroup\$ If you are just looking for a buzzer, there are countless decent products for just a few US dollars. Look for toilet/bathroom water alarms. They have two metal contacts and they make quite a sound! I'm sure you could adapt one to your needs. I built my own for use using a few BJTs and some MOhm resistors. Worked very well until the nice commercial units arrived in the mail. \$\endgroup\$
    – jonk
    Jul 24, 2021 at 8:27

1 Answer 1


Your water probably isn't a good enough conductor

As @Hearth noted in the comments, it's a safe bet that your water isn't the good conductor you think it is. While people typically say that water is "a conductor", that's a terrible over-simplification and the real question is how conductive the water is. The conductivity of water depends on many factors, and fresh water is actually a rather poor conductor. For example this Wikipedia article on conductivity notes that 1 cubic centimeter of ultra-pure water "could achieve 18 megohms or more." Hardly the same thing as a wire.

Two other concerns with this approach

  • Electrodes with DC voltages do not work well in water. Over time they experience polarization effects, so their performance will degrade over time until they just stop working. Even if the conductivity problem gets solved, this still wouldn't be a robust system.
  • The pipe you're using is specified for potable water. If this water is going to be used for human consumption, then it's strongly advised to avoid having any homemade components contacting the water. There are simply way too many opportunities for chemical or biological contamination of the water.

Another possible way to solve the problem

There are switches designed specifically to detect when water is flowing through a pipe. For example something like this. (Again, be extra careful if you're dealing with potable water, and make sure all your components are rated for potable water too.)


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.