I rescued a 2 year old male Maltese. I never was able to housebreak him.
Here is what worked for me:
1. crate him at night
2. confine him in the kitchen when I was not home
3. belly bands at all times!
4. Long walk in the moring after work & a shorter one before I went to work at 10 pm.
I cannot recommend belly bands highly enough! I never could have kept that dog for 16 years without the belly bands.