You can withhold your rent, make repairs and deduct the cost from your rent, work with other tenants to put pressure on the landlord, take your landlord to court or break your lease. You may want to consult with a tenant advocacy organization or a lawyer.
Tenants have a right to withhold rent because landlords are obligated to provide safe and habitable housing under the warranty of habitability. If a landlord breaks this obligation, a tenant's obligation to pay the full amount of rent stops until repairs are made. A tenant may want to withhold all or part of the rent, depending on the seriousness of the violations. The law does not state how much or for how long you can withhold.