(a) Full registration period

A sex offender shall keep the registration current for the full registration period (excluding any time the sex offender is in custody or civilly committed) unless the offender is allowed a reduction under subsection (b). The full registration period is—

(1) 15 years, if the offender is a tier I sex offender;

(2) 25 years, if the offender is a tier II sex offender; and

(3) the life of the offender, if the offender is a tier III sex offender.

(b) Reduced period for clean record

(1) Clean record

The full registration period shall be reduced as described in paragraph (3) for a sex offender who maintains a clean record for the period described in paragraph (2) by—

(A) not being convicted of any offense for which imprisonment for more than 1 year may be imposed;

(B) not being convicted of any sex offense;

(C) successfully completing any periods of supervised release, probation, and parole; and

(D) successfully completing of ¹ an appropriate sex offender treatment program certified by a jurisdiction or by the Attorney General.

(2) Period

In the case of—

(A) a tier I sex offender, the period during which the clean record shall be maintained is 10 years; and

(B) a tier III sex offender adjudicated delinquent for the offense which required registration in a sex registry under this subchapter, the period during which the clean record shall be maintained is 25 years.

(3) Reduction

In the case of—

(A) a tier I sex offender, the reduction is 5 years;

(B) a tier III sex offender adjudicated delinquent, the reduction is from life to that period for which the clean record under paragraph (2) is maintained.