Am I able to ask the Landlord to decrease the rent if he owes HOA fees (Single Family Home) and we are not able to utilize community facilities such as, swimming pool, gym due to monies owed by Landlord. We were never informed the Landlord was behind. We were informed that we would be able to use the facilities by the Realtor.

You can ask but if he needs the money I can't imagine he'll agree.

He is breaching his contract with you.