Faucet Locks

They sell faucet timers at Lowe's or Home Depot. It can be set to go off after so much time. You hook it to the faucet and then the hose to the timer and you can just leave it there. Below is a link to one from Lowe's.

http://www.lowes.com/pd_159978-74985-27729_###-###-####_?...

I've only been able to find one that requires you to remove the hose. If you are handy with woodworking I was thinking that maybe creating a box with hole in the bottom to let the hose out and a hinged lid on the top that can be locked with any regular kind of combo or key lock but it would be unwieldy and unstable unless anchored somehow but I can't think of how to do it. Maybe a rubber insert around the hole cut for the hose so it can "grip" it and keep itself anchored above the faucet knob?

Or you can punish your daughter for using the hose without asking and leaving it on, ensuring that she won't ever do it again, without permission first. She's five and should be able to understand that she made a mistake and you don't want it repeated without having to invest in elaborate methods to deter her. It's not like she's your neighbor who is purposefully stealing your water and you can't get her to stop by asking so you're forced to lock it up.

I'm sure your daughter can learn from this mistake and be taught not to turn on the water without permission first.

I take the handle off, it is just one screw on the faucet. I keep it in the kitchen out of reach. My son loves to make "magic potions" with water and icky stuff. This way there are no mistakes unless I leave it on. Kids can be sneaky when they are determined.

Oh my gosh! I'd hate to see your water bill!
I'm not sure if you can find a "simple" type of lock.
Your daughter is 5 and I would have a talk with her about messing with the hose and leaving the water on. She's old enough to understand that wasting water is a bad thing and when you get your bill, you might have to go without some things because water isn't free.
I would tell her that she is not to touch the hose without your permission at all, and if it happens again, she will be in big trouble.
I think the easiest thing would be to get a nozzle for the end of your hose so you don't have to worry about the water just running full force and just check a couple times a day, especially at night before bed to make sure the water is off. We had lots of faucets in my yard and I just periodically checked because in the summer with kids over, I never knew if one of them might think to get a drink out of the faucet and forget to turn it off.

Where I live in California, we had such a bad water shortage that we weren't allowed to use water outside at all and then eventually, only on certain days of the week. We were all on rations. I had so many bugs on my windshield that I could barely see out of it and I had a bucket in the yard with about two inches of old water in it. I got a squeegie wet so I could scrub my windshield before using Windex and paper towels and one of my neighbors called the police on me for "washing my car". I got a formal written warning, but thankfully wasn't fined.
My point is, when you go through something like that, you realize how precious water is.
Your daughter wasn't thinking...and forgot to turn the hose off. If you explain things to her, she's old enough to understand that leaving a hose on is not a good thing. If she were 2 or 3 I might say to invest in a lock if she's fascinated by water, but she's 5. Just like she's not allowed to be around the stove without your permission, she's not allowed to mess with the hose without your permission.
And don't tell her that a nozzle will keep from wasting water because she will be less likely to worry about turning it off if she does it again.
After she's gone to bed, you or your husband do your nightly rounds and make sure everything is off.

Best wishes!

Can you just put one of those garden hose sprayers on the end of the hose? The kind that needs to be squeezed like a spray bottle to work. It may still leak a bit with full water pressure, but at least it won't create a flood :)