As a landlord you have a duty:

1. To comply with current applicable building and housing codes;
2. Make all repairs and do whatever is necessary to put and keep the rental premises in a fit and habitable condition;
3. Keep all common areas in safe condition;
4. Maintain in good, safe working order, and promptly repair all electrical, plumbing, sanitary, heating, ventilating, air conditioning, and other facilities and appliances which you have supplied or are required by your agreement or any law to supply after you have been notified by the tenant of any defects in writing (in emergencies such notice does not have to be in writing).
5. to provide and install battery­operated or electrical smoke detectors and to place new batteries in a battery­operated smoke detector at the beginning of the lease.

You must perform any other duties required by your rental agreement. You may also be required to allow a tenant with a disability to modify the premises and accommodate that tenant`s needs. Except in emergencies, you must notify your tenants in writing of any breaches by the tenant of duties imposed on him by law.