The school's roll will be managed within the maximum roll prescribed in the school's integration agreement. The board will make provision for likely population movements in the general area served by the school that occur during the school year or after the end of the pre-enrolment period. The maximum roll is 720.

Applications for enrolment will be processed in the following order of priority.

First priority will be given to preference students who are boarders.

Second priority will be given to preference applicants for whom the school is reasonably convenient and who reside within the boundaries of Upper Valley Parishes (St Joseph’s Upper Hutt, and Our Lady of the Valleys Parish Heretaunga/Stokes Valley). Students within this priority group are guaranteed enrolment unless including all of them would exceed the school's maximum roll (and/or school capacity). In such a situation, students will be ranked for selection in accordance with the priority criteria listed below.

Third priority will be given to preference applicants who currently have, or have had, a sibling at the College. Students within this priority group are not guaranteed enrolment. If there are more applicants than places available, the priority criteria listed below will apply.

Fourth priority will be given to preference applicants who are sons of former students of St Patrick's College, Silverstream. Students within this priority group are not guaranteed enrolment. If there are more applicants than places available, the priority criteria listed below will apply.

Fifth priority will be given to preference applicants for whom the school is reasonably convenient and who reside within the boundaries of Lower Hutt Parishes of Te Awakairangi Parish (covering St Martin de Porres Church Avalon, Ss Peter and Paul Church Lower Hutt, St Michael's Church Taita, and St Bernadette's Church Naenae) and Holy Spirit/Te Wairua Tapu Parish (covering San Antonio Church Eastbourne, Sacred Heart Church Petone, Our Lady of Rosary Church Waiwhetu and St Patrick's Church Wainuiomata) and St Theresa Parish Plimmerton. Students within this priority group are not guaranteed enrolment. If there are more applicants than places available, the priority criteria listed below will apply.

Sixth priority will be given to all other preference applicants. Students within this priority group are not guaranteed enrolment. Priority among fifth priority students will be given to students according to the priority criteria listed below.

Seventh priority will be given to non-preference students. Non-preference students will be enrolled only if enrolment places remain after all preference applicants have been enrolled and the Board judges that enrolment of the non-preference students will not compromise its ability to offer places to preference students who may apply for enrolment at a later date. Priority among non-preference students will be given to students according to the priority criteria listed below.

1. Sons of Board members.
2. Sons of members of Board of Proprietors.
3. Sons of Board employees.
4. Sons of those who have been members in a key school organisation
5. If, having applied these criteria there are still more applicants than places available at any priority level, then the remaining places will be balloted.

Applicants seeking priority status may be required to provide proof of residence in the specified area.

If the total number of applications from preference students is less than the number of places available, all preference applicants will be enrolled.

The number of places available for non-preference students will be governed by the maximum number allowable under the school's Integration Agreement. For St Patrick’s College, Silverstream, a maximum of 5% of the roll (34 students) is permissible.

If the total number of applications is greater than the number of places available, unsuccessful applicants will have their names recorded on a waiting list, within their relevant priority category, ranked in order of the published priority criteria. Students on the waiting list may be offered places at a later date if places become available.  The  waiting  list  will  remain  current  until  the  Board  next  notifies  the  public  that  it  is  inviting applications for the next enrolment intake.

Each year applications for enrolment will be sought by a date which will be published in a daily or community newspaper circulating in the area served by the school.