I'm not sure about locking faucets, but I wonder how much it will help to have a foot touch turn on valve? Wouldn't he be able to do that too? The only thing I could think of would be to turn off the water at each sinks source, but that would be a royal pain.

Is he in a wheelchair? If yes, then maybe having the faucets and handles coming out from the walls would be out of his reach.

He's not in a wheelchair. His strength is his gross motor (walking and climbing) but he doesn't always understand what he's doing (functions mentally at the 15-month range). That means he'll turn a water faucet on, full blast, play with the water, squirting it all over the place, once shifted the kitchen faucet, putting full-blast water all over the counter top and cupboards, which spread all over the floor, which spread to the dining room... I have to keep my eyes on him at ALL times, but sometimes let down my guard. We now lock bathroom doors from the outside, but I can't do that with the kitchen.

I like the motion sensor idea, especially for bathroom faucets, in case someone forgets to lock the door (he once turned the bathroom sink on, full blast, and then left the room. I discovered the over-flowing water when the third floor bathroom leaked to the living room ceiling below. Groan.). He would not be able to understand a foot pedal, like one sees in hospitals, and I wonder how easily they are to add to an already existing kitchen faucet. We've tried turning the water off at its source but that is a pain. Maybe a combination of sensor and foot pedal on the kitchen would do it.

Anyone know of 'best brands' (ie, 'strong') for these products?

I should add that, so far, he hasn't turned on the bath or showers (knock on wood)! I have seen pull chain types to turn on, with the ability to lock on or off. They're used for folks with seizures (so that they have to pull the chain, turning on the water, and it will go off automatically if they're have a seizure). But so far he's left the bathtubs alone.

Mari, you might think about contacting someone who's specialty is Universal Design. People with arthritis might have difficulty turning water on and off with regular handles, so Universal Design specialists may have an idea for you. Just a thought. Good luck! I feel for you!

Or what about, for the bathroom at least, the type that you have to press down the main part and it goes off after a certain time or amount of water passes (like in malls)? If he can't figure out foot pedals, this may be another potential solution.