Lanthanum accumulation on a polarized unmodified electrode has been shown to be under local pH control. Cyclic voltammograms in unbuffered aqueous solutions have shown that the local pH varies up to 10 pH units compared to the bulk solution, while buffered solutions vary ~ 6 pH units. This is due to lanthanum’s theoretical deposition potential being well outside the working region of water, resulting in the consumption of proton-equivalents during water electrolysis. Previous work has shown that high pH induces lanthanum to become insoluble and thus unavailable for electrochemical reactions. The large background current from water electrolysis hides lanthanum’s electrochemical response during cyclic voltammetry experiments, so the electrochemical quartz crystal microbalance (eQCM) was used to track the frequency shift resulting from attached mass on the surface of carbon-coated QCM electrodes. Varying levels of buffering agent (acetate buffer) resulted in modulation of the onset deposition potential as well as the length of the stable film region during anodic stripping. This shows that bulk parameters (pH, buffer strength) can be used to determine the potentials at which lanthanum will deposit and strip on unmodified carbon electrodes.