I was at the tax meeting in 2007, and I know that the monetary amounts may have altered but the 'rule' then from the head office was...
If there is more than one owner of a house, the exception for the taxation of rental income is applied individually for each owner.
Also deductable expenses (deductable from the gross rental income) were,
lighting, heating and water.
management charges relalted to administration of rental property.
Insurance expenses of rented property and rights.
maintenance expenses of rented property
repair expenses of rental property
Again these were quoted in 2007. The tax office website (in English) is
http://www.gib.gov.tr/index.php?id=469