25 CFR §171.515

1. (a)We will bill the landowner, unless:
   1. (1)The land is leased under a lease approved by us, in which case we will bill the lessee, or
   2. (2)The landowner(s) is represented by a representative organization that collects annual operation and maintenance assessments on behalf of its members and the representative organization makes a direct payment to us on your behalf.
2. (b)If you own or lease assessable lands within a BIA irrigation facility, you will be billed for annual operation and maintenance assessments, whether you request water or not, unless otherwise specified in § 171.505(b).