<prompt> Human: I live in a share house with 3 other people. One of my housemates runs a small business from home and is claiming all of our bills on his tax.The rest of us kind of feel like its not quite fair. I was hoping to get a little advice on what is right and how to approach the situation.Edit: Its probably worth mentioning that I live in Australia.Edit2: Thanks everyone for your useful information, it sounds like old mate might be in a little trouble should he be audited! Assistant: Unless you also have a business, the cost of the utilities is not deductible to you and useless on your taxes. Likely hes filing it wrong anyway and if he gets audited he will be in trouble. Deducting utilities for home office is complicated and would never involve deducting all the bills if done correctly.Human: If he was doing it correctly, he should only deduct his 25 not 100 correct?  <response>: Even less - he only gets to deduct utilities attributable to the portion of the house used as a home office. So if 10 of the house is used as a home office, the deduction would be 10 25 utility bill.And, unless the are is regularly and exclusively used for the business, no deduction at all. So, if he is sitting in the living roomdining room working on his computer, that almost certainly isnt a home office. 