Housetraining a rescued dog

Question
My husband and I adopted a wonderful one-year old male Boston Terrier mix from the Humane Society about 2 1/2 months ago.  He adjusted well and is doing well with our whole family (2 daughters ages 5 and 6) and two rescued cats.  He doesn't have any accidents during the day when we are at work.  He is restricted to our kitchen during that time.  He also has no accidents at night.  We take him out consistently to the same place in our front yard first thing in the morning, right before we leave for work, and right when I get home from work.  He also gets a daily walk in the late afternoon.  We take him out right before we go to bed around 10 PM.  However, he continues to have urinary accidents in the late afternoon/early evening.  He doesn't have accidents in the same place.  It could be on the floor in different places or on our couches and our bed.  Many times he will have urination accidents right after we took him out and he seemed to urinate a lot.  He doesn't drink excessively, but he does seem to urninate excessively.  Do you think this is a housetraining problem?    

Thank you!

Answer
It could be a number of things. First the fact that he is male may make him feel like he has mark or 'claim' territory by marking,which can be a dominance problem and can be corrected by taking him to obedience school. They often will do it at certain times when you are busy and not watching them ect

The second thing you could try for that is to crate him in the afternoon,while letting him out every couple of hours to go

It could also be a bladder infection,in which a vet would have to see him-but based on the fact it's only at certain times I am more convinced it's a marking issue