It is found across Pennsylvania's northern half, and south through the Appalachians. In summer, the upperparts are browner and the underparts paler. The long tail is brownish-black above, paler below. The water shrew inhabits heavily wooded areas and is adapted to a semi-aquatic life. The banks of cold, clear streams provide optimum habitat.
Water shrews occupy small surface runways under bank overhangs, fallen logs and brushpiles.
They also live in bogs and springs, and may shelter in a beaver lodge or muskrat house in winter. Nests are usually made of dry moss. This shrew uses its big hind feet, fringed with short, stiff hairs, to paddle about under water. It can stay submerged about 15 seconds. Water cannot penetrate the shrew's dense pelage, so the animal itself never gets wet.