The aim of the present study was to establish an aquatic biomonitoring network for the Galician Environmental Specimen Bank (BEAG) (NW Spain). For this, a sampling system was designed that comprised of 121 points distributed throughout Galician rivers, from which samples of water and of three species of bryophytes were collected. The results obtained allowed selection of 74 sampling points and 2 species (Fontinalis antipyretica Hedw. and F. squamosa Hedw.) as the most suitable for use in future BEAG sampling surveys. The two species selected showed a strong similarity in their capacity to accumulate the 17 elements determined (Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, Se and Zn), as well as in their ecological preferences. Furthermore, the levels of contamination of epicontinental waters were lower than those observed in previous surveys.