IRS pub 425 says, "Passive activities include trade or business activities in which you don't materially participate. You materially participate in an activity if you're involved in the operation of the activity on a regular, continuous, and substantial basis. In general, rental activities, including rental real estate activities, are also passive activities even if you do materially participate. However, rental real estate activities in which you materially participate aren't passive activities if you qualify as a real estate professional. Additionally, there's a limited exception for rental real estate activities in which you actively participate. The rules for active participation are different from those for material participation. You can find guidelines for determining material participation, the rules for determining who's a real estate professional and what's active participation, and the special rules that apply to the income and losses from a passive activity held through a publicly traded partnership (PTP) in Publication 925,"
Basically, rental is generally passive unless you are a real estate professional, HOWEVER, refer to pub 925 for special rules.
Pub 925 says, "Rental Activities
A rental activity is a passive activity even if you materially participated in that activity, unless you materially participated as a real estate professional. See under Activities That Aren’t Passive Activities, later. An activity is a rental activity if tangible property (real or personal) is used by customers or held for use by customers, and the gross income (or expected gross income) from the activity represents amounts paid (or to be paid) mainly for the use of the property. It doesn’t matter whether the use is under a lease, a service contract, or some other arrangement.
Exceptions.
Your activity isn’t a rental activity if any of the following apply.
- The average period of customer use of the property is 7 days or less.
In my brain, the IRS says that rental is generally a passive activity. Unless, you are a real estate professional, or average rental of 7 days or less.