The work is based in Harrisburg and covers the towns a reasonable drive puts within reach — the West Shore boroughs and Cumberland Valley out through Carlisle and Dillsburg, the Hershey and Hummelstown side of Dauphin County, and down the river through Middletown to Elizabethtown. Same approach at every address: the foundation gets assessed before anything gets proposed, the system gets designed to that specific house, and a retest verifies the result. Each town below has its own page, because the housing stock — and the way radon behaves in it — genuinely differs from one to the next.