Inland Revenue collects tax from most income sources. In most cases, income from renting out a property and in some cases from having boarders in your home or hostel will be classed as income and tax will apply.
You can watch an introductory video about tax on rental income on the Inland Revenue website(external link).
For more detailed information read the Residential property section on the Inland Revenue website(external link).
If you have paying boarders living in your home Inland Revenue have a calculator that will help you work out if you have to pay tax on this income. Standard cost home-based boarding services calculator(external link).