I never heard of a timer for a shower (although that doesn't mean they don't exist), but perhaps a better approach would be to install an ultra low-flow shower head. By federal regulation, all new showerheads must dispense no more than 2.5 gallons per minute. There are, however, showerheads that dispense much less. The link below will take you to info on a showerhead that dispenses just 1.25 GPM, but there others available that dispense even less. Most include technology that mixes air with the shower stream so that the force of water feels as though more water is flowing. Do a google search on "ultra low-flow showerhead" and you'll find many others.

If that doesn't work, maybe there's some timer mechanism out there that will cause the shower door to fly open after a certain amount of time, or a siren to go off... ;-)

Here is a link that might be useful: Ultra Low-Flow Showerhead

Timed valves are available...they're not always stylish, as they tend to be used more in commercial than residential.

Some are controlled locally, like in the shower itself, others are remote.

A google search should put you on your way.

If she is a good kid, sit her down and explain the problem. Ask HER to come up with solutions. Maybe she will surprise you.

My teenager with the shower problem was my bonehead son, and we agreed he would set the timer every time he got in the shower (I bought a drugstore kitchen timer) and he was told if I don't hear it going off in 10 minutes followed by the water, I'm coming in there myself. End of problem. He only showered when I was home, so it was inconvenient to be the shower police, but in his case it was what it took.

Good luck.

I agree with Lady.... treat her like a young adult and involve her in the problem. Explain and then listen.

If she doesn't come up with the idea on her own, then setting a kitchen timer/alarm that she would bring in the bathroom with her should do the trick.

If a timer really shut things down then I think you'll just cause aggravation and frustration. Suppose you were in the middle of rinsing your hair or shaving your legs and the water went off? That is frustrating enough in a hostel or campground shower, but at your own home it would be pretty lousy. Relationships with teens can be iffy at times and I can't imagine how I'd have felt if my mother had done something like that to me!

The enviro website where I also hang out, Grist, had an identical question a few months ago (Amy, was it you?), with a few answers. A few gadgets were mentioned, but the best answer sounded a lot like GBSim's -- treat her as a young adult. Link attached.

Here is a link that might be useful: Teenager's long hot showers

If you can't get your hair rinsed in the first ten minutes, then you deserve to have shampoo in it when the timer goes off . . .

anyway, discussion seems best. Followed by downsizing the water heater to 15 gallons or so.

Conversation is best followed by telling her she can pay the water bill for the next 2 months. That will cure the problem quickly. We had same problem with our kids and I laugh now at how quickly my DD can take a shower now that she pays her own bills - she who used to let it run for 30 min. or drain the hot water heater. I offered to let our DS pay the water bill and he "got the message" quickly.

I mentioned this posting to a friend of mine. She said she had a similar problem with her daughter. She found a novel way to fix it.

Her daughter's bathroom was one of those in the middle of the house without a window, so the light always had to be on when someone was in the bathroom. When no amount of reasoning with her daughter would get her to take shorter showers, Mom put one of those timer switches on the bathroom light that automatically turns the light off after 15 minutes. Since the switch was too far to be reached without getting out of the shower, her DD had to either continue in the pitch dark, or get out of the shower before all went black. Once she was out, she usually stayed out.

Anyway, not a solution for everyone....but it might work for some.

OK here's my update...actually I have just enacted the kitchen timer method. First I timed myself to make sure I wasn't being cruel. (It took me 4 mins. 52 sec. day 1 and 5 mins 20 sec the 2nd day when I took the time to just "stand there awhile.") So I gave her 8 minutes. I put the timer across the room and it does aggravate her when it goes off but she gets out. It sounds like we're all on the same page as I had just suggested to my husband the timed light idea before reading this post. However I think if I can train her with the kitchen timer, we'll be good.

Good news!!

Just out of curiosity does she have siblings? Does she share a bedroom? Sometimes the shower is the only place that kids with sibs that share living space can have time to themselves.

check this whower timer, works reallyd well https://www.youtube.com/watch?v=AJoaej6kNBo

I know this is a very old thread. I just wanted to say that for some reason, I take really long showers. I know as an adult, it's different. But I think there is a timer on my shower (I rent a room) and it pisses me off. I rush through the shower and have to alternate my tasks. If I do my hair, I can't shave. If I'm all set with both I can quickly clean up and just enjoy my shower. Sometimes that's all I do. Hot showers are a popular go to for comfort. Maybe the reason someone is in the shower for 30 mins is more emotional than anything else. Just my .02.

A teenager taking a 30 minute shower is looking for privacy, not cleanliness. Put a lock on their bedroom door and the showers will shorten. And stop snooping through their room.