Water Level Sensor https://www.adafruit.com/product/3397
12v NC Water Solenoid Valve - 1/4" water line https://www.amazon.com/gp/product/B0743CSRFF/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
Arduino Nano ( or whatever you want ) https://www.amazon.com/ARDUINO-A000005-DEV-ATMEGA328-NANO/dp/B01873ITV8?keywords=arduino+nano&qid=1540312707&refinements=p_89%3AArduino&rnid=2528832011&sr=8-1&ref=sr_1_1
Arduino Nano Breakout Board https://www.amazon.com/gp/product/B00X3L2RJK/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
Momentary Push Button
https://www.adafruit.com/product/1009
2x 100k ohm resistor ( pull downs ) LED light 220 ohm resistor for LED Wires Soldering Board / Breakout board / whatever 12v Power supply
1/4" tubes/connectors/shut off valve
I used 1/4" water line to feed my system. My friedgerator already had a line feed to it that I just T'd off of. I then used the shut off valve to also act as a cheap regulator. I did this so the water just trickles out vs blasting out at full pressure making a mess and scaring my cat.
12v power supply brick to run to relay/solenoid valve. Cut 12v wire to plug into relay. Then relay to the solenoid valve. Then Ground wire from solenoid valve back the power brick ground.