You could easily be $100k in for water/gas/power/sewer if you’re talking 4+ lots. 

Maybe the P trap under the sink is not filling with water correctly and allowing sewer gas to come back in.  

Right now we are just finishing out this year before we really put the gas pedal to the floor. 

In my current roll, I manage 17 shopping centers of various sizes and select sites for new gas stations in the Arizona market.

If you want to quote out high efficiency boilers for six Tripple deckers for example requiring installation of separate gas, meters etc. etc. - that might be a situation where you would want to work with a contractor directly because you would have lots of different options with widely varying costs.

Utilities are OFTEN overlooked so reach out to power, telecom, gas (or go all electric), water, and sewer to make sure you understand what it would take to get separately metered services from the primary house.

So, if your property has all bills paid by the tenant, you will deduct from the voucher amount the set amount by bedroom count for items like water, electric, gas, etc.

:)As for LTR rental terms, usually we sign a 1 year lease where tenants are expected to pay Electric and Gas if applicable, while the owner typically pays water/sewer/trash with the city. 

I underestimated utilities in my early years, so I ensure those are properly captured (electricity, gas, water and trash).

They'd also probably be more aware of how much water, gas, or electric they are using when they have to pay the bill after each cycle.