If the HOA is legally responsible--e.g. under your deed, the complex's master deed, and/or the documents governing the HOA--for repairing this leak, then they are also responsible for any resulting cost or damage from their failure to properly make repairs.Withholding HOA fees is not the way to resolve the situation, since you may then have to contend with liens and/or a foreclosure attempt on your unit. If the HOA is not honoring its obligations, the way to protect your rights and interests is to sue them, either for monetary compensation and/or a court order (injunctive relief) requiring them to correct the situation. You should consult with a real estate attorney.