When you're a resident landlord the taxman's going to be very interested in the rent coming in. Generally, any source of income you've got is going to get his money-antennae twitching. The tax you'll pay depends on more than just the rent you charge, though. As a landlord, there are quite a few essential costs you have to pay out to stay in business. These expenses can count against the profit you're making from renting your room out, bringing your tax bill down. Wear and tear repairs, replacing furniture and many other costs can be counted as business expenses.