25 C.F.R. § 171.545
What can happen if I don't pay my bill on time?
(a) We will not provide you irrigation service until:
(1) Your bill is paid; or
(2) You make arrangement for payment pursuant to § 171.550 of this part.
(b) If you do not pay your bill prior to the close of business on the 30th day after the due date, we consider your bill past due, send you a notice, and assess you the following:
(1) Interest, as required by 31 U.S.C. 3717. Interest will accrue from the original due date stated on your bill.
(2) An administrative fee, as required by 31 CFR 901.9.
(c) If you do not pay your bill prior to the close of business of the 90th day after the due date, we will assess you a penalty, as required by 31 CFR 901.9(d). Penalties will accrue from the original due date stated on your bill.
(d) We will forward your past due bill to the United States Treasury no later than 180 days after the original due date, as required by 31 CFR 901.1, “Aggressive agency collection activity.”