As I'm sure you know, each rental is it's own "like-kind" activity to the other rentals. With like-kind activity, the passive losses of one activity will offset the gains of any of the other like-kind activities. So if you have one rental that shows a $1000 taxable gain and the other three rentals show a $1000 loss each, your total among those like-kind activities will be a $2000 loss. For rental property the losses just accumulate with each passing year as they are carried forward. So in my example you would add that $2000 loss to any carry-forward losses from last year.
It is not common for rental property to show a gain "on paper" at tax time. In fact, it's more common for rental property to show every increasing losses with each passing year. This is especially true if there's a mortgage on all properties. But if you have for example, one property paid off which means there's no mortgage interest to deduct, that one property very well could show a gain that will start offsetting losses on the other properties.
I'm in that situation now. Paid off one of my three properties a few years back. That one property started showing a taxable profit in the years after that, which took a few years to use up all my losses on the other two properties.Because of that I'm now showing a taxable gain on my rental income. But I don't have a problem with paying taxes on money I get to actually keep.
