The city of Denver has one of the highest compliance rates of any city in the nation. (73% as of February 2020.) 

I have the opportunity to purchase 4 houses on contract and was looking for input before pulling the trigger.

Question, at 42 how much cash flow did you have before you pulled the trigger?

If sales for top-dollar move-in ready remodels and new builds start slow this year, it could begin triggering market activity that will benefit investors.

I understand you get what you give, but if I have a compliance question, I expect an answer i a reasonable amount of time.

If it is already stated in the lease that tenants pay utilities give notice of non-compliance with lease. 

Either way, you tell them they will have a serious credit issue on their credit report, eviction or judgement, if they don't pay what they owe you.If you do the above, all you did was write a letter and it is usually sufficient to scare them into compliance. 

I am getting ready to pull the trigger on my first fix and flip property in the Indianapolis area.

Market is hot here, if you find something you like, pull the trigger.  

Also, when you know what you are looking for, pull the trigger fast!