Is it because the gas connection was turned off and this heater needs gas to operate?

If you're interested in multi-family, I highly recommend starting out with multi-family with your first VA loan as it will be easier to get a single family residence after that.If you decide to pursue multi-family, you'll want to ensure that each unit is separately metered for utilities (water, gas, heat, electricity, etc.) as this is a requirement under VA financing.  

Do you have the money to have a new heater put in it of some sorts, electric baseboard, natural gas, propane- as well as a new water heater.

Check under sinks if you can, many times slow leaks occur there that go unreported.6.

never heard of one running off propane, unlike natural gas or electric.

Chances are, you will never get out of it what you have put into it (gas, maintenance, taxes, etc.)

Cap Ex was relatively high last year due to a water line leak wiped out a good portion of the profits the Cap Ex that year was around 48%of rent since rent was lower.

On Saturday, 6/29, in the late afternoon, for the second time within two weeks, the sewer trap was backing up....thank God for leak sensors. 

There is an 18billion dollar gas plant that is being built in Brownsville on the Port and is expected to bring in 5k new jobs. https://gcaptain.com/nextdecade-finalizes-18-billion-investm...I'm also told that Rio grande valley is booming in growth around areas like Mcallen and brownsville. 

Today I went to look at the meter and I didn't see a constant usage that I thought would be a sign of a leak in the pipe between the meter and the shutoff valve.