It is mainly restricted to riparian habitats (rivers, streams, swamps, marshes and dams), wherever there is suitable vegetation cover and water in close proximity. It may also be found along estuaries and in coastal areas. Sometimes it is found away from watercourses, though only for limited periods (Baker and Ray 2013). Diet comprises mostly aquatic prey with crustaceans often dominating, which is unusual among mongooses (Baker and Ray 2013, Do Linh San et al. unpublished data). However, in some areas rodents constitute the main prey in terms of biomass (Maddock 1988).

This species is widely distributed from Senegal, Guinea-Bissau and Sierra Leone eastward to southern Sudan and Ethiopia and south to southern Africa, where it is absent from most of Namibia, Botswana and large parts of central South Africa, wherever adequate water and cover are unavailable (Baker and Ray 2013). It is present on Pemba Island, but absent from Zanzibar (Pakenham 1984). It has been recorded from sea level to altitudes of 3,950 m asl in Bale Mountains N.P., Ethiopia (Yalden et al. 1996). Wozencraft (2005) lists this species as occurring in Algeria, presumably an error as there are no confirmed records from this country (M. Ahmim pers. comm. 2013).

This species is present in several protected areas across its range.