25 CFR §162.250

1. (a)Unless an agricultural lease provides otherwise, we may enter the leased premises at any reasonable time, without prior notice, to protect the interests of the Indian landowners and ensure that the tenant is in compliance with the operating requirements of the lease.
2. (b)If an Indian landowner notifies us that a specific lease violation has occurred, we will initiate an appropriate investigation within five business days of that notification.