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For nearly two decades, stream baiting of northern and central California coastal streams has been an important tool in the management of sudden oak death, a devastating forest disease caused by the oomycete Phytophthora ramorum. Phytophthora species are baited with floating rhododendron leaves, serving as an early detection tool for the presence of P. ramorum in watersheds across more than 800 km of California coastline. While this long-standing management tool is focused on a single species of Phytophthora, other species of Phytophthora have been baited alongside P. ramorum, and this study documents the presence and distribution of 22 Phytophthora and Nothophytophthora species across the northern and central coasts of California. Although P. ramorum was isolated at the greatest number of sites, several species in subgeneric clade 6 were also abundant and widespread, a common feature of Phytophthora stream baiting studies. Clade 3 species P. nemorosa, P. pluvialis, and P. pseudosyringae were also frequently isolated in northern coastal streams. The species Nothophytophthora caduca and the genus Nothophytophthora are reported for the first time in North America along with the first report of P. pluvialis in California. Two novel species, Nothophytophthora sp. californica and P. sp. aureomontensis (a member of the P. citricola species complex) are provisionally named. Mitochondrial sequences revealed multiple hybridization events between P. lacustris and P. riparia. Stream monitoring can serve as an important tool for monitoring ongoing Phytophthora invasions as well as establishing baseline pathogen communities, critical data for preventing future invasions.