  We introduce dissipative effects in the effective field theory of
hydrodynamics. We do this in a model-independent fashion by coupling the
long-distance degrees of freedom explicitly kept in the effective field theory
to a generic sector that "lives in the fluid", which corresponds physically to
the microscopic constituents of the fluid. At linear order in perturbations,
the symmetries, the derivative expansion, and the assumption that this
microscopic sector is thermalized, allow us to characterize the leading
dissipative effects at low frequencies via three parameters only, which
correspond to bulk viscosity, shear viscosity, and--in the presence of a
conserved charge--heat conduction. Using our methods we re-derive the Kubo
relations for these transport coefficients.
