I adopted a 18mo old husky about almost a month now. The old owners said he was housetrained and it seemed really believable in the first few days. I would take him to the backyard and he would pee, occasionally he had accidents and it was probably because he was adjusting to the schedule. I would clean it up and spray it with an enzyme cleaner to rid of the smell.
Although he didnt have accidents that often anymore, he still would about twice a week. And it isnt the same spots as well.
Just recently hes been having accidents more frequently. I would take him out around the same schedule every day. (at most a 30min difference). Often he would pee when we're just heading downstairs about to go out to pee. I took him to the vet too, they said its just him adjusting to the new environment and nothing was wrong with him. He is unneutered, which means during our walks he would stop at every tree to mark it. And that's the reason I believe is behind this.
When he goes to the backyard he would always pee a little and start wondering around. I tried giving him treats when he pees outside, but i dont think he associates it with that. Just yesterday he peed inside when i wasnt watching, so immediately i took him outside, where he pee'd a bit more. When he started wondering around again , i took him inside so i can clean up the mess. But when i was cleaning, i heard him pee again inside the house. So again i took him outside.
Before when i catch him in the act i could scare him enough to make him stop but now he doesnt listen at all. I have to drag or push him a bit for him to stop. He doesnt circle around and sniff before like people say, so predicting that is out of the question.

I am thinking of neutering him, but i dont know if this is related to neutering, and it it will solve it.

TLDR: 18mo husky is unneutered, pees in the house. When i take him out he doesnt empty the tank.

(also: he doesn't pee when I'm at work or not around. )

And the vet cleared him for not having a UTI? It sounds like a UTI.

If he definitely doesn't have a UTI don't let him wander the house when you are home. Keep him tethered to you so he can't pee when you aren't looking without you being able to correct him at the proper time. I would also get him fixed. Some dogs it doesn't make a difference in the peeing (it does make life easier with other things) but some it makes a huge difference. My newer male completely quit marking once he was fixed and now empties the tank when he pees. And I mean really empties it. You can wait a good bit for him to pee it all out. Are you crating him when you are gone?

The vet never mentioned UTI. I asked for a general exam and brought some droppings for bacteria checks. Should I take him back and specifically ask for uti?
I don't know about being tethered. I once leashed him and as I was putting on my shoes, he peed right there.
I don't, but I'm really considering it. He seems fine in the house when I'm gone so I didn't get a crate. But I ordered one couple of days ago should be here in a few days

Also his urine seems to be really thick and pretty yellow, I don't know if that's a symptom of uti. We have this rock in our backyard that I used for him as a spot to pee on, and there's a stain on the rock from one time he peed on from maybe 2 weeks ago