They can contact me the same way the building inspector of another borough contacted me when I had a code violation (cracked sidewalk)...via US mail based on the mandatory tax property address on file for the the property.  

Never heard of such a thing, you own the property, the sidewalk is an easement, the city or HOA usually owns the sidewalk.

The tenants were walking on a plank sidewalk to avoid stepping in feces AND they had two young children living down there.

Taxes, commissions, and other Tax Claim Bureau fees and expenses go first, then other state liens, Federal liens, municipal liens like water, sewer, trash, improvements like sidewalks, then mortgages, judgments and liens. 

For example, if I'm pouring a sidewalk to a front door with 1-2 steps, I slope the sidewalk to the landing and backfill to the top of the concrete resulting in a natural sloping sidewalk.

Desmond strikes me as the kind of guy that talks a big game about equality and multiculturalism in society ,but hurriedly rolls his window up and locks his doors of his bmw when he sees a brown person walking his way down the sidewalk .

We email owners if tenant has not paid by 5th of month, but they often still want to speak with bookkeeping about it.Some property owners want to be informed of every single tenant maintenance complaint, from drip in faucet to neighbor tossing butts on the sidewalk;  those owners want to decide for themselves what to do. 

The third I purchased is almost complete (still need to pour a driveway and sidewalk as soon as we get out of this deep freeze) and I should do even better on it.

About 2-3x month there is someone in the neighborhood digging up the sidewalk or street to replace a curb trap or one of the lines.

They provide a beautiful breeze but we have three of them including a bathroom window that go right out into the sidewalk on a well used side of the house, what were they thinking?