And inspect their house for water leaks in plumbing.

(Gas, water/sewer, trash, lawn care etc.)

I will have to pay for the water because it’s not separate meters.

The Home has electric heat and the landlord pays for the water/ sewer 110$ per month.

Yes, but you need to narrow it down a lot to have a coherent answer.You will have to look at (I'd recommend in this order) the city codes (if it's inside a city, many cities above 50-100k population aren't friendly to development of these), the county codes (most counties are friendly to these, but you will probably have significant issues in major counties like Bexar, Travis, Dallas, Denton, Tarrant, Harris, etc), then you will have to comply with the state-level (TCEQ and others) on the water supply and waste water treatment systems.To put it in perspective again, in say Dallas or Austin, you will likely have prohibitions or very significant hurdles on developing RV or tiny home properties even on unincorporated, "unrestricted," AG-zoned properties at both the city/municipal level and county level.

Once you do get in the game, and you start to put together a portfolio, you'd be amazed at how quickly the brush-off turns into the warm welcome.

@Jonathan Bombaci thanks so much for the warm welcome and the awesome points of advice, particularly your last point.

For the extreme level, that includes a dramatic drop in reservoir and aquifer levels, the implementation of water use restrictions, and impacts on wildlife and agriculture.

To determine if it's worth doing a 4-Plex in addition to the cost you listed, I would recommend looking at; is the lot already graded, and ready for construction, are sewer, water, and gas already at the lot for connection, what type of rents are on your proforma, the biggest one many people forget about are the developer fees charged by the municipality to allow you to build the project, etc.There are a few soft cost items that will be a part of the project that do not get lower just because you're doing a smaller project.

I appreciate the warm welcome.