Yup. Just as simple as that. With the pull down in place I get 0-4 on that pin when dry. And between around 50-300 when wet, depending on a few drops of water or cable fully submerged.

Now I just need to piece everything together, both hardware and software. Trying to make a fail safe for my hydroponic system. The only way it can fail catastrophically, and flood my downstairs neighbors place, is if the drains fail and the pump keeps running. I'm using the leak sensor rope to go around my buckets and trigger a relay that will kill the pump at the first sign of any water under the buckets.

Yup. Just as simple as that. With the pull down in place I get 0-4 on that pin when dry. And between around 50-300 when wet, depending on a few drops of water or cable fully submerged.

Now I just need to piece everything together, both hardware and software. Trying to make a fail safe for my hydroponic system. The only way it can fail catastrophically, and flood my downstairs neighbors place, is if the drains fail and the pump keeps running. I'm using the leak sensor rope to go around my buckets and trigger a relay that will kill the pump at the first sign of any water under the buckets.

Correct, at least it sure looks to be floating like crazy in the serial monitor. The only examples I found using this sensor just mentioned 5v to one of the black wires and the other going to A0. Guessing the voltage is jumped when water connects the two wires. Was mentioned in another forum that he had no/minimal changes with a resistor so I never tried it. I'll try adding one tonight when I get home. Super new to this and jumped right into my intended project after only trying a few very basic example files. Certainly have gotten ahead of myself. I have a mega as my project board, and an old Diecimila that I found at work in an old desk. I've been using that to test chunks of code for various parts of the project.

Thanks for the nudge in the right direction.

Re: Water Leak Detection

I didn't really want to necropost but the forum gave me the option to start new. I picked up one of these Honeywell extension cables, mostly because the length is about perfect for my needs and not having a ton of extra sensors. When I hook up 5v to one of the black wires and the other to A0 I don't get values close to what this old thread describes. With power to it, and no water, the numbers are all over the place almost like it drifts with the breeze. I've only seen this cable referenced for arduino in two different places, and both were places that @TD22057 has posted. I've really hit a wall with this sensor. Anybody else using these? Or have some code examples for this cable?