Urine deep in carpet?

well you said you found the spot but have you attempted to clean it? maybe all you have to do is shampoo the rugs and im just saying that even though your cats are well behaved they could still be doing this ecspecially since your saying its a new house that could stress some cats out and cause them to have an accident or haveing nothing to do with the new environment i had a cat that when she got old about 12-14 she started peeing on the floor always in the same spot and i dont know why oh also do not dump a bunch of cleaner on your floor i dont really think that will work but if you do decide to do that seal the area off for your cats saftey