The design behind leak sensors is actually pretty cool: essentially, most sensors have two or three metal probes that, when they come in contact with water, detect increased conductivity and set off an alarm. It's an elegant solution to the age-old problem of flooding.
But D-Link takes an even more creative approach. Rather than using probes, D-Link's Wi-Fi Water Sensor uses a cable with long, twisting leads embedded in it. You can run the cable along the edge of your basement floor, say, and if water touches it anywhere, the twisted leads detect increased conductivity and set off an alarm. It's a little like what we did whenlast winter.
D-Link is unique for more reasons than the cable, though. The base unit also plugs directly into a wall, negating the need for batteries, and connects via Wi-Fi to your phone -- cutting out the smart home hub middleman that limits so many other flood sensors ($33 at Amazon).
The result is a solid product with a slightly higher price of $60 (compared with its $40 competitors that work with SmartThings or Wink).