What matters for project planning
Gutters themselves sit outside all of this; where they discharge does not. Naperville requires property owners to maintain on-site stormwater control facilities, which means roof runoff has a destination the site was designed around, and a downspout that simply ends at the foundation is working against it. Because the city's plan relies on storm sewers, detention basins and overflow routes, discharge that overwhelms or bypasses those routes becomes a neighbor's problem quickly on the lot sizes typical here. Sizing outlets for the roof area draining to them matters more than the gutter profile above.
Official sources
Verify the property, not just the city
Citywide context cannot establish a parcel’s flood zone, historic designation, permit requirements, soil conditions, or concealed construction. Verify those items directly with the relevant authority and your chosen provider before work begins.
Sources reviewed 2026-07-26. External requirements and maps can change.