My basenji Kaia just turned 4 years old. We've always had a bit of difficulty getting her entirely housebroken - she messes in the house every once in a while, but had a months long streak of being good. The only common denominator in her messing in the house is that she typically does so when we've left her alone in the house (even though we have a 9 year old German Spitz at home as well). However, in the last week she has messed in the house EVERY. TIME. we go out. It's gotten so bad my parents can't even go sit outside without taking her out because if they do she'll piss on the kitchen floor. We've put a gate up to quarantine her in the kitchen as punishment and have taken to doing so when we go out just to keep the pee contained, but without fail, there's a puddle when we get home. We're running out of ideas. Any insight/tips?
We dealt with that issue with our Basenji's. The first one was anxiety peeing. Soon we got him a sister and he stopped instantly. The other one had reoccurring urinary issues and we would often find her peeing to get her urine tested and sure enough she needed antibiotics. So that may be the issue. We also had weather pee-ers. So if it rained a lot or we watered the grass a lot we have to watch out for pee. We had to learn her triggers. Thunder is a bad one too. The point was though she would then wait for us to leave and then go pee upstairs. So now if it is raining, wet, cold or thundering we have to take her outside and keep chasing her until she finally pees. Then she is fine and can be left in the house just fine. Also, she doesn't want to get out of bed sometimes but we have to kick her out to pee. Also if she is in the kitchen make sure the other dog is with her too or she will get upset and pee. Sometimes they even pee if they are upset about any type of change. Good luck!
This sounds like separation anxiety. However, it would be good to check with your vet and find out whether she has a urinary tract infection. Punishment isn't a great idea, as it will make her even more anxious and likely to pee. Definitely make sure she has emptied her bladder before you leave her alone. Is she crate trained? If so, you could try crating her when you go out and see if that helps.
If you could arrange to video her actions when you leave, it might give you some insight. If it is separation anxiety it would be best to find something to distract her when you are going out. I used a roller ball with treats in it for my boy, and it worked very well. Most often dogs with separation anxiety do their damage right after you leave, and if you can keep them occupied they may well be O.K. because they are distracted during the time they are usually most anxious.
Obviously I agree that a vet check for a medical issue is first and foremost. The dramatic increase is a signal that something medically is off-- could be urinary track, hell could be crystal or thyroid or many things. A full evaluation is called for anytime your dog has a sudden change or increase in a behavior.
However, >>We've always had a bit of difficulty getting her entirely housebroken - she messes in the house every once in a while, but had a months long streak of being good.<< is not a great sign. Even if she has a medical issue, you still have a problem because you have a dog that is not housebroken and it is so much better to spend the next 3 or 4 months really addressing this than spend the next 8 to 10 yrs living with it.
Housebreaking is a bit like being pregnant... you are or you aren't. Sure, a sick dog doesn't count. But unless sick, or some crisis leaving a dog so long it has no option, pottying in the house is simply not okay.
So once you get the medical checked out, go back in time, and retrain as if a puppy. It's a little easier since she already knows to go out when you are home... but a whole LOT harder because when she does potty, you generally aren't. I see no way to do it without returning to crate training, not just when you are gone, but home also. Basically you are going to have to go out with her to potty, sing her praise, give her a treat. Take her out when she gets up in the morning, every 3 or 4 hours during the day, after meals, before bedtime. If she doesn't ever potty in the house at night, great. If she does, then her new sleeping zone is a crate. It helps if you have one where she generally sleeps and a 2nd on near the main action for during the day... because you need to start putting her in the crate when you cannot actively watch her even when you are HOME until you get 100 percent no house accidents. I'll put a couple of links with clear instructions.
Since this mostly is if left alone, separation anxiety might be the stimulus. Sometimes medications for a while, plus really good toys they only get when left alone (especially mind stimulating ones like Shirley suggested), Kongs with some smeared cream cheese or peanut butter (don't use a lot!! Keep a couple in the freezer!), safe chew toys, can help get the dog over the anxiety. Talk to your vet, because you can't effectively do housetraining while not helping with the separation issues.