How long does it take? Ridding a building of pests can take anywhere from a few hours to weeks. It all depends on the specific circumstances. The larger a building is, the longer it can take to get rid of pests. Another factor is where the pests are – If they’ve deeply infiltrated spaces that aren’t easily accessible, it will likely take extra time to get rid of them. Certain species are more tenacious than others, and it may take some time for an exterminator to verify that the infestation has been removed. An exterminator should be able to give a fairly accurate timing quote at the onset of taking the job.