There are many behavioral and physical signs of a possible urinary infection, however these can also indicate other illnesses which are sometimes even more serious, such as kidney disease. If you suspect your dog’s urine is abnormal you need to have him examined by a vet as soon as possible. Behaviorally, dogs will either relieve themselves more often (which often makes it seem like they have forgotten their house-training, such as in your case) or have difficulty urinating. Your dog might also develop an obsessive cleaning ritual. Physical signs of a possible infection include pus, blood or crystals in the urine and lower back pain. There may also be a marked increase or decrease in the volume of urine produced.