The Simcoe County Housing office that provided the tenant’s income is not under any obligation to release personal information about their clients to any third party. All businesses in Canada, even landlords, are subject to the Personal Information Protection and Electronic Documents Act (PIPEDA). Personal information may be stored and disclosed only by fair and lawful means, with the individuals consent, and only for purposes that are stated between the parties. The other problem you have is that even if you find out the employer information on your own, and begin to garnish the wages by taking the employer to Small Claims Court, the tenant could quit their job. If this happens, the garnishment payment to court and to you would stop, and you would have to start again once you find out who their new employer is.