In some of its residences, Studierendenwerk offers apartments to families or single parents and their children. Addresses and important information such as how to obtain an apartment can be found on the student residence (Wohnheim) pages  of the website of Studierendenwerk Berlin.
Accommodation allowance (Wohngeld ) is a state subsidy provided to cover rent, and as such any money received does not have to be paid back. Accommodation allowance is not intended to cover other living expenses and applicants are, therefore, required to prove that they have sufficient income to cover such additional living costs. The amount of accommodation allowance to which an applicant is entitled depends upon the number of family members, the level of family income and the rent. Accommodation allowance cannot be paid retroactively. Application forms and an online calculator for accommodation allowance entitlement can be found on the website  of the Senate Department for Urban Development and Housing (Senatsverwaltung für Stadtentwicklung).
In principle, international students are also entitled to apply for accommodation allowance. Should problems arise with the foreigners' registration office (Ausländerbehörde) when making an application, the applicant can withdraw their application for accommodation allowance. It is recommended that applicants contact the International Student Counseling  to obtain information before submitting an application.
Social housing qualification certificate (WBS)
Students with lower incomes can apply to receive a social housing qualification certificate (Wohnberechtigungsschein or WBS for short) from their local district office (Bezirksamt). The WBS qualifies you to rent apartments which are state subsidized. Pregnant students can, from the 14th week of pregnancy, claim for additional living space requirements for the child they are expecting when submitting an application. It is also possible to apply for a joint WBS together with the father of the child.
International students can also obtain a social housing qualification certificate if they have a residence permit which is still valid for at least one more year.