Q: Can the new property owner keep partial security deposit?

A: Assuming your rental was in Oregon, the new owner is both liable for, and entitled to, the security deposit just the same as the old owner was. To the extent that he alleges damages beyond ordinary wear and tear, he may charge you for it and deduct it from your security deposit, so long as he provides you with a written accounting within 31 days of you restoring possession to him. If you disagree with the accounting, and cannot resolve the issue informally with him, your remedy is to sue him in court for twice the amount wrongfully charged, be it small claims court or regular circuit court. The burden of proof will be on him to show that you damaged it (it was not preexisting if you claim that it was); it was beyond ordinary wear and tear; and the amount he is charging you is reasonable and properly depreciated if applicable. One of the potential issues here, however, is that the winner will get a Judgment against the loser for their attorney's fees (if in regular circuit court) and those fees most likely will exceed, perhaps considerably exceed, the amount being fought over. Hence both sides have a strong interest in reaching a negotiated settlement rather than rolling the dice to see what a Judge rules. Do be aware that even if you sue in small claims court where neither side has an attorney, and the amount is for more than $750, they will have the option to force it out of small claims court. That would leave you either having to drop the matter or file in regular circuit court where both sides can, and should, have lawyers.