In most states, sidewalk law is a shrug that points at your city. Illinois and Pennsylvania are more direct: state law explicitly hands municipalities the power to order you, personally, to build or repair the sidewalk in front of your property, on a clock.
Illinois: the 30-day letter is in the state statute
65 ILCS 5/11-84-2, verbatim: "The ordinance shall require all owners of lots, blocks, tracts, or parcels of land touching the line of a proposed sidewalk to construct or repair a sidewalk in front of or touching upon their respective lots, blocks, tracts, or parcels of land in accordance with the specifications of the ordinance, within 30 days after the mailing of notice of the passage of the ordinance, addressed to the party who last paid the general taxes."
Read that again: 30 days from the mailing of the notice, sent to whoever last paid the property taxes. And the companion section (11-84-1) lets the city pay for the work "by special taxation of the lots... touching upon the line" if you do not. The Illinois machine is: ordinance, letter, 30 days, then it lands on your tax bill. Our verified Chicago record shows how the state's biggest city handles the sewer side.
Pennsylvania: the borough can order the whole package
The Borough Code, 8 Pa.C.S. Sec. 1801, gives boroughs two distinct powers, verbatim: any borough may "lay out and establish sidewalks, curbs, gutters and surface water drains along any street," and separately "may also require owners of property abutting on any street or State highway to grade, construct, drain, pave and repave the sidewalk, curb or gutter and keep them in repair and in safe and usable condition."
Note the breadth: not just the sidewalk slab, the curb, the gutter, and the ongoing duty to keep them "in repair and in safe and usable condition." In Pennsylvania boroughs, the owner-pays rule is not a quirk of one town's ordinance, it is the express design of state law. Our verified Philadelphia record covers the state's biggest city (a city of the first class with its own code, and no tree-root exception).
If the letter arrives
- Check the clock and the specs. In Illinois the 30 days runs from mailing, not receipt, and the work must match the ordinance's specifications, a non-conforming DIY repair can be rejected.
- Get your own quotes fast. Doing the work yourself within the window is almost always cheaper than the city's contractor plus administrative costs landing on your taxes.
- Ask what triggered it. If the damage traces to a city tree or utility work, raise it in writing before the deadline, not after the assessment.
Sources: 65 ILCS 5/11-84-1 and 11-84-2 and 8 Pa.C.S. Sec. 1801, both quoted verbatim from the official legislature sites. City rules live in the complete city guide.