Urine odors

Question
I have a 10 month old Puggle  who was house trained but lately has been urinating on the carpet.  I have tried to remove the odor from the carpet using products from PetSmart but the odor is still there because the dog goes back to the same spots again to urinate.  Are there any commercial products available that are used by breeders or vets to take care of this problem?  Also do any of these products come in large quanities that can be used to clean large area of carpet using a shampooer?  Thank you in advance for any help you can give.

Answer
There are several commercially available products to remove urine stains and odor.  The ones that contain baking soda are best.  A product called "Zero Odor" works well, but is a little costly.  You can find it online.  A homemade remedy is "Woolite". It works very well and will not discolor carpet.  It removes odor and stains, including skunk odor on your pet.  Mix a capfull of "Woolite" in 2 quarts of water.  Rub in and let set.  Rinse carpet with clean water after a couple of hours.  On your pet, pour on and leave on.