I ALWAYS have separate pros inspect the roof, HVAC, structural (if something is seen that warrants it), sewer main (or, septic, including separate sewer scope for drainfield AND perk test), and water well (bacteria and pump flow, etc.), if not on public water. 

We also have a lot of homes with a lead water pipe, which needs to be replaced, which usually means digging up the front yward to the street.

The tenants on the property i'm looking to buy are reporting that they need to add water to the toilet after use in order to get it to flush and often that results in water coming up from the bathtub. 

The most cost effective way to treat for any airborne virus, is to use bleach according to food safety specs or regulations.A bleach and water solution used for cleaning, is your friend.

I have already cannibalized the property and used the hot water heater, stove etc in other rentals. 

Call the local water authority and get some actual numbers.You're forgetting CapEx.

Confirm with local water authorityLawn care/snow removal: $50-150/month depending on location and property specificsOther shared utilities: Property dependentTrash removal: Property dependentPest control: Property dependentProfessional/Admin fees: $25+/month depending on the size of the property to cover tax filings, advertising, etc.

.), Taxes (Property & Other), Depreciation, Business Mileage, Education & Training, Bank Fees, Employees, and Independent Contractors, Repairs and Maintenance, Insurance, Property Management Fees, Supplies, Utilities (Oil, Gas, Electric, Water, Phone, etc.), Home Office Expenses, Travel Expenses, Snow Removal, Landscaping, Pest Control, etc., HOA Fees, Business Meals (50% deductible), that doesn't stop you from cash flowing growing equity and someday retiring wealthy.

or the tenants take have free water and electricity?

Water issue seems resolved later part of the last year.