S. palustris likes herbaceous covered banks of swift flowing streams and creeks (Webster et al. 1985). Often associated with grass-sedge-willow, or some combination thereof, vegetated shorelines of mountain streams (Whitaker and Hamilton 1998). Conditions around beaver ponds and broadened slower-moving lengths of streams are also suitable habitat for this shrew. Also, found in bogs, intermittent creek beds, muddy grass-choked spring heads and rocky areas near water.

NATURE SERVE GLOBAL HABITAT COMMENTS:

Most abundant along small cold streams with thick overhanging riparian growth. Also around lakes, ponds, marshes, bogs, and other lentic habitats. Rarely far from water. Nest sites are near water in underground burrows, rafted logs, beaver lodges, and other areas providing shelter.

Van Zyll de Jong (1983) described the habitat in Canada: 'Lakes, ponds, swift and sluggish small streams, all provide suitable habitat if adequate cover is available in the form of overhanging banks, boulders, tree roots, logs, etc. In the mountains, the species occurs along cold fast mountain streams. On the other extreme, it is also found in stagnant water of marshes or bogs, and a few have been caught in places with very little water. The water shrew appears to have some flexibility in adapting to habitats with little water or even to habitats where water is present only seasonally. However, the species appears to be most abundant along cold mountain streams with abundant cover.'

Pagels (1990, 1991) noted that in the southern Appalachians the water shrew is limited to prime habitat: 'high elevation situations where moist, cool, shaded situations have prevailed throughout historic time...elevations ranging from about 762 m (2500 ft.) in Pennsylvania to 1158 m (3800 ft.) and above in North Carolina and Tennessee. In addition to close proximity to water, habitat features often include moss-covered rocks, crevices, fallen trees, and boulder-strewn and/or overhanging stream banks. Understory vegetation is generally dense with mountain laurel and rhododendron being the most abundant species.'

In Montana, Conaway (1952) examined 101 capture sites and found typical habitat to be 'along fast cold mountain streams having banks which offered favorable cover.' All these shrews were trapped within 18 cm (7 inches) of water.