My landlord refused to fix water seepage now won't return deposit. Do I have a case?

My slumlord moved me into an apartment with a water leakage. I'm not talking about a drip or two from the ceiling. I'm talking when it rains, the rain comes in through the ceiling and down the wall. The wall is warped from the damage. My son has asthma and has been sick a lot since we moved here in January. We suspect that the constant leaking is causing mold behind the walls. The city came out and inspected four times since January. Each time giving them 30 days to fix the leak or they get a ticket. They have been accepting the ticket. Now that I see they have no intention of fixing it, I told them I was moving out in a couple of weeks. Now the landlord says she is keeping my deposit. If you ask me, she broke the lease. I cannot afford a lawyer, but I just want a general opinion before I go through all the trouble of trying to afford a lawyer. Do you think I have a case?