An automated multiplexed pumping system (MPS) for high frequency water chemistry measurements at multiple locations was previously reported. This technology showed potential to increase spatial and temporal resolution of data and improve our understanding of biogeochemical processes in aquatic environments and at the land-water interface. The design of the previous system precludes its use in volume-limited applications where highly frequent measurements requiring large sample volume would significantly affect observed processes. A small volume MPS was designed to minimize sample volume while still providing high frequency data. The system was tested for cross contamination between multiple sources and two applications of the technology are reported. Cross contamination from multiple sources was shown to be negligible when using recommended procedures. Short-circuiting of flow in a bioreactor was directly observed using high frequency porewater sampling in a well network, and the small volume MPS showed high seasonal and spatial variability of nitrate removal in stream sediments, enhancing data collected from in situ mesocosms. The results show it is possible to obtain high frequency data in volume-limited applications. The technology is most promising for observing pore water solute dynamics and improving existing solute transport models for saturated or partially saturated soils and media.