That will yield about $100-200/month in profit = $1200-2400/year. That’s 6-12% profit from the $20k invested from the very first year. That sounds pretty decent to me considering rent will most likely go up over time, which will increase your ROI. The question is, can it really fetch $1800/month in rent?
And $1200-$2400 profit assumes you’ve got it rented 12 months/year. I think vacancies and maintenance are likely to wipe that profit out completely in the long term.