House-training a fully grown dog?

[snowyowl]

We just got a second dog, and while her foster said she was house-trained (though she hadn't been when the foster first got her), I had a sneaking suspicion we might be in for trouble. It was something about the way the foster said she hated correcting this dog because she was sweet and shy and a few other comments. Turns out I was right, and I'm wondering if there are any different strategies when a dog is fully grown as opposed to a puppy.
Here we are, 24 hours later, and she's already had three accidents in the house. I've kept a careful eye on her, but she doesn't sniff around or circle at all, she just suddenly goes. She also doesn't care if there are people around (my first dog would sneak around and only pee in the house when no one was looking). So she'll go trotting into the room with me right behind her, pee, then I'll do the clapping, tell her no, and take her outside where she will happily stare at me until I give up and take her back in. I'm also taking her out frequently. We've only crated her twice so far - overnight and when we went to run some errands today. She had no issues in the crate so we'll do that when we aren't around.
Anything else I should be doing? She is probably around two years old, so these habits could be pretty ingrained. I could try tethering, but I suspect she would just go anyway. She has only gone on carpeting so far, which most dogs seem to prefer, so I could hang out solely in our hardwood rooms, but we tend to spend most of our time in our carpeted den, so I'd be sitting out in the dining room all the time or leaving her alone in another room, which I don't have any desire to do. 
On top of that, she takes a minimum of 15 minutes to find the perfect spot outside to go to the bathroom. What the heck, dog! You pick a spot on the carpet in .5 seconds! 

[clo]

Sounds like you are doing all the right things. Tethering would help in that you could easily catch her in the action (and if you are constantly moving, she won't have time to squat).

New dogs = potty accidents in any house. Give her a little bit of time to get used to your house and what she can and can't get away with. Her life just turned upside down, and she will appreciate some consistency.

Make sure you are cleaning all of her spots with an enzymatic cleaner.

[G22]

When we adopted our husky mix, she was 2 and had potty issues. We were told she was abandoned by her previous family. They moved away and left her in the house.(how long, we don't know) So she got in the habit of going to the bathroom inside. So when we adopted her, she had accidents inside still.

We found that crating definitely stopped the accidents while we were gone. And when home I constantly would make sure she had chances to go out to potty. I think the fact that we had another dog already helped. So when I would take them outside and say "go potty" and he would go, she slowly caught on. I'd make sure to tell her "good girl" and make sure she knew when she went potty outside, it was a good thing. Treats could help too.

It took a few weeks and we did use a leash to tether her next to one side of our bed at night for awhile. She would occasionally sneak away and have an accident while we were sleeping, and that seemed to work as well. She also would wine if she needed to go in the middle of the night, so we would hear her this way.

I agree with the PP. She's in a new place with new people and its overwhelming. That may be contributing to it some.

[caz1221]

I generally treat adult dogs the same as puppies in terms of house training - take them out often; praise/reward/treat like crazy any time they potty outside; tether or crate them in the house; if they start having an accident or circling/sniffing, whisk them outside immediately and praise/reward/treat like crazy if they potty at all (even a few drops) outside. I also use a potty command ("go pee") - initially, I just say it as the dog is peeing/pooping, but eventually, I can tell them "go pee," and they understand what to do. If you aren't already, I find taking the pup out on a leash and walking them around helps them go - if they're off leash or by themselves, they can get easily distracted and "forget" why they're outside. No playing until they potty. Finally, make sure you're cleaning up any accidents with an enzymatic cleaner like Nature's Miracle. Regular cleaners may mask the scent from people, but dogs can still smell the pee/poo and then will think it's ok to potty in that spot again. Good luck - there tends to be a transition period when you bring a new dog into the family!

[snowyowl]

Thanks for the replies! I kept doing what I was doing and added more treats, praise etc. It is likely that you all are right, this was mostly a new place, lots of changes issue. She went inside a few more times, but this week she is accident free. She just needed to settle in and get a sense of the routine I think.
I got a little overly stressed because our first dog, whom we got as a puppy, took FOREVER to be fully trained.