Super Simple Water Level Control

Design a simple water controller in which electrodes are required to sense high and low water levels in a tank. Whenever the water level falls below the low level electrode, the water pump starts and it stops once the water level touches the high level electrode. There is a third electrode which is used to detect the water level from the pump suction port tank. If this electrode does not sense water, then the pump is not allowed to run. This protects it from burning out. Power is obtained from the AC line through an AC-to-AC Wall transformer. The control electronics and relay work from a 12VDC voltage regulator. It is assumed that you have a water pump already.

*** Disclaimer: This kit is meant to operate with equipment such as line operated water pumps or motor starter relays and/or contactors at lower control voltages. Line voltage is dangerous and if mishandled can cause injury or death. If you are not familiar or have not worked with line operated equipment, have a licensed electrician do the power wiring for you. This kit is meant to be educational in nature and can be used with line operated equipment if National Electric Code guidelines are followed. ***


bruce54819 (Feb 01, 2017)
I bottle maple syrup is there any way to make this control a solenoid valve, would need switch to turn on and switch to bump to top off bottle and then auto shut off when fill? thanks for any help
rlarios (Jul 23, 2017)
I guess you already know how long it takes to fill up a bottle of maple syrup. Having said that, you could have a timer circuit that would start timing as soon as you switch to turn on, energize solenoid valve and turn it off once time is up.

MAM85 (Oct 25, 2016)

Can this water level control kit be adapted to pump out water condensation from my furnace using maybe a wall wart powering a 12v pump placed inside a catch container? The pump would set in a low level of water at all times. When the condensation reach a certain level the pump would cut on and pump back to the low level


rlarios (Jul 23, 2017)

With a couple of changes this circuit can do exactly what you want.
Desertrose (Dec 07, 2014)
I'm not in this field.
Please help me out,
I knew 12AC in X1
4 position for sensors X2, X3.
X4 120AC IN?

rlarios (May 06, 2015)
The relay contacts make or break the 120Vac hot leg. You just wire this hot leg first to one of the relay contacts, the other contact goes to the pump. The return wire from pump goes to neutral.

Sorry about the delay, it's been a while since I last checked the comments.

MikeP (Jul 11, 2014)
Does motor com on immediatly when water contacts sensor 3? I need a circuit with 4 sensors so that well sensing for pump shutdown is done with a sensor at the bottom at pump and sensor 4 to re-activate pump when water level reaches a certain point above pump say at 100' above lower sensor #3.

rlarios (Jul 13, 2014)
Hi there MikeP,

Click on the "buy this kit" button on this Club Jameco project so you go to Jameco store. You will find a video done by Jameco personnel after they put together this kit for the first time. This video will show you the water-sensor/motor response time you are asking about.

If distance between sensor and common ground wires is a problem, you can run an additional "ground" wire next to the wire you intend to use to sense level at 100' so the circuit detects logic levels properly.

Hope this helps.

MikeP (Jul 14, 2014)
Hi Riarios

The problem I have and requirement is such.
When tank calls for water, need pump to start and fill. when water level drops below pump level pump shuts down. which I will call probe 3. Then as well recovers and water rises, the pump would not start when it hits # 3 and waits until it contacts probe #4 which would be positioned approximately 100' above. The time for well recovery for the 100' is about 18 which time pump would restart and pump down to probe # 3 to restart wait cycle to #4 until tank full when probe #1 which is at high level of tank would stop pump.

Thx for indulgence
rlarios (Jul 15, 2014)
Hi MikeP,

I think I understand now what your problem is. If you still feel I didn't understand it, please let me know.

It seems to me that you want a sump pump control combined with this water level control. If this is the case, you can modify this water level control to work as a sump pump control whose output would function as "pump protect" signal for a second unmodified water level control board. This means you would need two of these water level control boards.

See the discussion I had with "thetrims" in the comments section at: for more information on how to modify this water level control to work as a sump pump control.

If this is the case, I can help you with a schematic to show you how what you mentioned below could work.

If I still don't understand your needs, can you please send me an email with a rough schematic of how your 4 probe control should work showing both, the tank and the well? My email address:

broandrew (Jan 29, 2014)
Hello Riarios, Can one us 12v DC to power the water level control board ? Can I just not use the 4 diodes after the 2 pin wire terminal ? ? Will it still work?
My application is a auto (car) application from a 12v DC source.

and 2nd ? What if we have electrolyte in the distilled water ( NaOH or KOH) ? In which gives less resistance in the water ? Can we change the resistors for water sensitivity ? This is for an HHO application.

Thank You
rlarios (May 04, 2014)
Hi broandrew,

I had not noticed your posting here 'till today. Sorry about that.

I believe that in order to have the 12Vdc coming from your car, you would have to go straight to the output of the on board 12V voltage regulator. This means you would omit the 4 diodes you mentioned plus the capacitor at the input of 7812 and 7812 itself as well. You would only keep the 7812 output capacitor and the rest ofthe components for the controller to work.

Regarding your second question, if your water has greater conductivity (lower resistivity) than tap water, you would not need to change pull up resistors as your lower resistivity would ensure that water presence can be detected more easily.

Hope this helps.

Luisco (Apr 13, 2013)

Hi, amazing project, I am looking foward to buy this kit, but before I buy it where can I find or buy this electrodes to complete the circuit with the tank ? reply here or e-mail me : thank

mistic (Nov 23, 2012)

Good project to apply. I had a water back-up problem in my home sewer so I made a sensor system to to alert me, I used copper wire sensors in the main but found that they will corrode in a couple of months. I am now using stainless steel wires. They corrode very slightly. You might want to use such sensor wires inside of the tank.

mistic (Feb 15, 2013)

Is the PC board standard or did you design one?

rlarios (Feb 27, 2013)

I designed it, go to:

Luisco (Apr 13, 2013)

Hi, where did you find the electrodes, please reply me or send me an e-mail : thanks