In rodents, the glymphatic system is critically involved in the clearance of brain waste products. In humans, the coupling (i.e., correlation) of resting-state functional MRI signals of global grey matter (gGM-fMRI) and the cerebrospinal fluid signal in the fourth ventricle (CSF-fMRI) is thought to reflect macroscopic glymphatic fluid movement, suggesting relevance for brain clearance. However, direct evidence linking gGM-CSF coupling with brain clearance measures is still missing. We hypothesized that in humans, gGM-CSF coupling is associated with two other measures of the glymphatic system, namely ventricular PET-tracer clearance and FLAIR-based extra-cerebral meningeal lymphatic tissue volume.To test this hypothesis, we examined the lateral ventricular 18F-DOPA-tracer clearance rate using simultaneous 18F-DOPA-PET-MRI of 16 healthy controls. The gGM-CSF coupling was calculated by Pearson’s correlation coefficients of fMRI signal time courses from grey matter and the fourth ventricle. Volumes of meningeal lymphatic vessels (MLVs) surrounding the superior sagittal sinus were derived from FLAIR-MRI scans, using deep-neural-network-based segmentation.We found a positive Pearson correlation between ventricular tracer decrease rate and gGM-CSF coupling. Furthermore, coupling was associated with the volume of MLVs.These findings demonstrate a link between gGM-CSF coupling with both 18F-DOPA-ventricle clearance rate and extra-cerebral lymphatic tissue volume. Data suggests that gGM-CSF coupling relates to brain waste clearance in humans.