It's a water heater for a Single Family Household.. 4 people live there..

.: The house is owned by Mom, and Friend is ‘running’ the household while Mom is away, and Person is Friend’s sibling - The horrendous ‘Tenant’Thanks so much in advance!

I'm glad you've all had positive experiencesThis article is very recent but specific to Miami https://news.wjct.org/post/miami-has-highest-household-vacancy-rate-among-largest-metro-areas-study-finds An exerpt:The Miami metro area has the highest number of households that are for seasonal or occasional use, followed by New York.

Does he have anyone who can contribute to household income?

When you screen tenants you should be ensuring that their combined household income is at least 2-3x's your rent amount.

Its purpose is to provide protections for state, tribal, and federal employees and their households in the event of a government shutdown.

If your daughter is not your dependent, then the home in question must be used by you (or a member of your household) as a residence for the greater of 14 days or 10% of the number of days the house is rented at FMV for you to qualify the house in question as a second home and deduct your share of the "personal" mortgage interest on your Schedule A.You most likely do not meet the threshold to call this house a second home but might be able to through planning.The other question, the question that you did not ask in your OP, is about the mortgage interest allocated to the rented bedrooms. 

It was not very common in typical household paint and regular single family style homes. 

I understand you can use this loan to make household repairs but to what extent?

Added expenses at the outset would be furnishings, decor, household items, linens, etcMonthly expenses would include property management, housekeeping, landlord insurance, utilities, internet/cable, lawncare, etc.Any help or advice is appreciated!