  We determine the sensitivities of short-baseline coherent elastic
neutrino-nucleus scattering (CE$\nu$NS) experiments using a pion decay at rest
neutrino source as a probe for nonunitarity in the lepton sector, as expected
in low-scale type-I seesaw schemes. We also identify the best configuration for
probing light sterile neutrinos at future ton-scale liquid argon CE$\nu$NS
experiments, estimating the projected sensitivities on the sterile neutrino
parameters. Possible experimental setups at the Spallation Neutron Source,
Lujan facility and the European Spallation Source are discussed. Provided that
systematic uncertainties remain under control, we find that CE$\nu$NS
experiments will be competitive with oscillation measurements in the long run.
