§ I · The surface
Picture a duplex off 21st Avenue South.
A 1948 duplex three blocks from 21st Avenue South. Walking distance to coffee, restaurants, three universities. The kind of address that books in a weekend.
§ II · The hidden layer
the 21st Avenue commercial spine carries decades of station and cleaner records — including more than one site with documented solvent detections that, depending on local groundwater gradient, can migrate hundreds of meters into the residential blocks east and west. Whether your address is on the upgradient or downgradient side is a parcel-level question.
§ III · What the records show
Representative findings within range of typical Belmont / Hillsboro addresses:
§ IV · The bottom line
21st Avenue's commercial spine carries decades of station and cleaner records. Variance is moderate; pre-1960 builds nearer the corridor see more findings.