Just because the costs might be in the furture does not warrant not budgeting for those known expensesThen there is the misc costs of asset protection, bookkeeping, unexpected utilities (such as between tenants (tenant turn over) or failure not attributable to the tenant such as slab leak).  

Add some nuk power generation FINALLY and lower household utility costs another 5%, adding a bit more to disposable incomes. 

If you have high holding costs (financing, taxes, insurance, utilities, etc.) the longer you are holding the less money that you are makingSelling profitably - How long will it take to sell?

Originally posted by @Kelly Watkins:Residential developers in Wichita pass the cost of the neighborhood utilities (sewers, streets etc..) onto the buyer.

The important things to consider about HOA fees is that they usually include some utilities: Water/Sewer, Trash, sometimes shared amenities like gym, clubhouse, pool, and they are saving you the time and headache for property maintenance: lawn care, tree timing, roof, siding, etc.

Utilities, including common area will also be different.

There are definitely faster ways to grow your portfolio fully utilizing debt.

Prepare for additional costs: If you’re adding units, you’ll likely need to address the water meter situation and possibly upgrade utilities.

STR management is 20-25% (I would recommend self managing or getting a VA), since income is higher you could probably get away with 5% for maintenance / cap ex but remember you need to cover utilities and cleaning for these units which drives up costs.

And have you thought about building back utilities?