Substance‐dependent mothers, who have grown up with parental substance abuse, struggle during and after treatment to abstain from substances while trying to process traumatic experiences and integrate their family into society. The aim of this study was to explore the social support available for these mothers to help them stay abstinent and create safe family environments for themselves and their children. Using purposeful sampling, we approached nine mothers admitted for 1 year to a family ward at a substance abuse clinic and their significant others. Through in‐depth, qualitative interviews, first with the mothers, later with their significant others, we investigated characteristics of the available social support. The findings indicated that the significant others had limited resources and were themselves exposed to adverse and cumulative psychosocial and socioeconomic risk factors. Their relationships with the mothers were, nevertheless, close, consistent and reliable. Supporting the existing social network should be an integrated part of the work of family welfare services aiming to help substance‐dependent mothers from families with parental substance abuse to rehabilitate and to integrate successfully into local communities.