I moved into an apt. that was previously bedbug infested. Just in a few months, I found out that what I thought was skin allergy was really bedbug bites. I lost my job as a result. The apt was sprayed but in a few weeks, I'm being bitten again. I brought it to the attention of the exterminator as I realized that the possible source of the bugs was the basement. At nights I can clearly see light shining from there when my lights are off in my bedroom. Not having a steady job anymore I called the office to ask for rent forgiveness since the loss of job was because of the bugs. I was told no but they would allow me to pay for August, in installments. Not seeming to have much choice in the matter, I agreed. Now bugs seem to be coming from the basement back in my bedroom. I have new bites.
Landlord / Tenant Lawyer
There is no legal requirement to reveal past or present infestation. That being said you need to send notice according to the lease. If he does nothing withhold the rent and escrow it.
I would also call the Board of health and have them inspect.