I thought I had a leak but have had the whole system looked at and nothing was found.

IT is costing me about $24,000 to do this because I have to bring the electrical system in both apartments up to current code, plus buy new HVAC units and all new ductwork separating the units and water heaters. 

A system in place where the broker guides you to pick a strategy or niche?

in addition to waste oil tank, there could potential PCBs from leaky lifts and impacts from motor disposal well or septic system if was used at site.  

I was thinking something along the lines of a Ring system, coded entry knobs, and a few cameras up high on the corners of the building also.  

Here are my few feel free to add more.Flexible (this game is unpredictable so you have to be willing to adjust accordingly).Patience (Especially in the beginning it takes time to get systems in place and people in place). 

Come up with the system you want to use that will best benefit you, and then write it into the lease.For example, if you are only going to take certified funds (money orders, cashier's checks etc.) then write into the lease that is all you will take and it is due by the 3rd of the month (or whatever you want it to be).That way in the future, when your tenants sign the lease you can prevent any disputes by just saying "According to the lease you and I both signed and agreed to..."

Any steps after this should be done by an attorney, unless you know the ins and outs of your local court system (pro tip: you don't).

If you consume less than your system produces, your credit from the utility can offset that amount too.If you think of a rooftop solar system as a "fuel tank".

@Ernes SahicA real estate broker that specializes in the particular multifamily property type has the systems in place to find off market deals if needed.