Groundwater & Basement Water Intrusion in Hinsdale, IL

That is a plausible and documentable connection. A replacement house with a bigger footprint, a wider drive, and regraded ground sheds more water than what it replaced and can direct it differently. Photographs and video during rain, with dates, showing where water now enters your property, are the record that makes the conversation productive. Village grading and drainage requirements for new construction are also worth reviewing, since they set what the new lot was supposed to do.

It does, in one specific way. A deeper basement sits further below the seasonal water table, so during a wet spring it experiences greater pressure on the walls and floor than a shallow one, and the drain tile has to run more to keep up. Newer construction includes that tile, which older houses often lack, so the net position is usually better. What it is not is exempt, and a pump failure has more consequence at that depth.

Yes, and it is the practical answer while the wider system is what it is. A backwater valve on the building sewer closes when the public line surcharges, which is the mechanism that puts water through a basement floor drain. Combined with a sump on independent backup power, it addresses both the surcharge and the groundwater. Neither depends on anyone else's timetable, which is their main advantage.