It can even be on a napkin.

Napkin math here.

This is napkin math takes 30 seconds.

It's like the old anecdote about Picasso - a woman came across him at Paris cafe and asked him to doodle something for her on a napkin. 

The palmer valve directs ground water (storm water) into the sanitary sewer which is why municipalities, especially ones like Milwaukee with a combined sewer, encourage homeowners to replace when appropriate. 

Use all electrical, plumbing, sanitary, heating, ventilating, air conditioning, and other facilities and appliances in a safe and reasonable way.D.

(A) A landlord who is a party to a rental agreement shall do all of the following:(1) Comply with the requirements of all applicable building, housing, health, and safety codes that materially affect health and safety;(2) Make all repairs and do whatever is reasonably necessary to put and keep the premises in a fit and habitable condition;(3) Keep all common areas of the premises in a safe and sanitary condition;(4) Maintain in good and safe working order and condition all electrical, plumbing, sanitary, heating, ventilating, and air conditioning fixtures and appliances, and elevators, supplied or required to be supplied by the landlord;(5) When the landlord is a party to any rental agreements that cover four or more dwelling units in the same structure, provide and maintain appropriate receptacles for the removal of ashes, garbage, rubbish, and other waste incidental to the occupancy of a dwelling unit, and arrange for their removal;(6) Supply running water, reasonable amounts of hot water, and reasonable heat at all times, except where the building that includes the dwelling unit is not required by law to be equipped for that purpose, or the dwelling unit is so constructed that heat or hot water is generated by an installation within the exclusive control of the tenant and supplied by a direct public utility connection;(7) Not abuse the right of access conferred by division (B) of section 5321.05 of the Revised Code;(8) Except in the case of emergency or if it is impracticable to do so, give the tenant reasonable notice of the landlord's intent to enter and enter only at reasonable times.

So most common "back of the napkin" rules that you hear on BP just dont translate over to Boston at all.

BUT when these same folks go to a local bank, or Hard Money Lender or Friends and Family they seem outraged if they have to supply any more than some numbers on a cocktail napkin;-)

If a receipt for cash payments is requested, you are legally required to provide one (although it does not have to be a pre-printed one, a paper napkin would do, albeit not recommended).If the tenant claims they paid (but haven't) they need to provide a receipt for it as proof.Re. the sec. deposit: Sounds like your property wasn't bank-owned.