This is way more than any rat poison or sprays can provide on a 24hrs / 365 days basis. However, a proactive approach is recommended. Rats may sometimes enter the area due to a survival need like escaping from a cat / dog or flooding during monsoon season. They will not be able to withstand RATOSONIC for long, and user may occasionally see paw marks or rat urine and faeces. User is advised to get it cleaned up. This is how rats mark territory. Once they start thinking the marked space is their domain, they may try to resist the ultrasound distress. In a worst-case scenario, they may even chew on something due to the agitation caused by RATOSONIC, as chewing de-stresses them. But our experience and customer feedback show the extent of damage caused would be far less than without RATOSONIC installed.