USCIS considers pretty much everything that results in monetary gains (other than investing) as "working". Even renting your own house counts as working, so people on H1B can't do that either.
You can’t have anything that even resembles a job, either paid (active income) OR unpaid if it may replace a paid US worker.
What if the renter plugs a toilet and you unplug it yourself instead of hiring a plumber?