Delta's using a new touch feature on some of their new kitchen faucets. This feature is what Delta calls Touch2O™ technology and it's pretty slick. Here's a demo video from Delta that shows how it works. I'll explain how it works in a bit.
So what's going on here is that the faucet and handle have an incredibly faint electrical current running though them. The current's supplied by a battery pack that's installed below the faucet. The power level is so low that it's imperceptible and since it's coming from a battery pack and not household current, it is physically impossible to get a shock from this system. Please make a note of that.
The lynch pin of this low-level current system is a solenoid valve in the base of the faucet. You can see the solenoid in section B of the illustration below. It's the box the water supply line runs through. A solenoid valve is essentially an electronic switch, and in this case it works like a master switch. When someone turns on the faucet, the solenoid comes to life in a manner of speaking. With the water turned on from the source and the temperature set, all you need to do to is touch the faucet spout or handle and the water will turn off. Touch it again and the water turns back on. Since this is a battery-operated system, the batteries will need to be changed periodically. Delta took this into account and integrated an indicator into the faucet. At the bottom of the fixture, there's a small LED light that shines blue when the system's activated. When the batteries start to go low, that blue LED will flash red.
There's also an automatic, four-minute cut off built into this system. If the water's left running for four minutes with no activity, it will turn itself off. A further cool feature of this technology is that it never takes over the manual operation of the faucet. At any point, someone can turn on and off the faucet conventionally, at the lever.
The whole point of this kind of switching technology is to be able to avoid touching a faucet handle with the dreaded "chicken hands." It's a perfectly valid concern by the way, "chicken hands" are an obvious source of cross contamination woes. Anybody who's suffered a bout of salmonella poisoning will tell you that practicing sensible hygiene around food is a very good thing indeed. Touch2O™ makes it easy to be smart and sensible and congratulations to Delta are in order. You can read more about Delta's new products on their website.
Finally, someone asked me on Friday if one of these faucets can be turned on accidentally by a meandering cat. The answer's an unequivocal no and a better question is why do you allow your cat climb around on your kitchen counters? Now the answer's a no because a human being has to turn on the faucet's handle from the get go. Unless you have a cat that can turn on a faucet manually, you're fine. Well, you're fine so far as the cat turning on the faucet goes. Clamoring cats bring with them a whole raft of other cross contamination woes, but I guess that's part of the joy of cat ownership. Right?