Analysis of seismogenic stress variations and their effect to crustal fluids is often complicated due to the singular and irregular occurrence of earthquakes and unknown origin of the associated stress changes, which lie deep in the crust. Utilizing external stress variations (tidal force and atmospheric pressure) whose source is known and which exert permanent load upon the rocks and induce similar changes of their permeability and other parameters seems a promising alternative. We plan to conduct monitoring of deep CO2 discharge and of groundwater level in the seismoactive western part of the Bohemian Massif and analyze the correlation and phase of the external stress field, CO2 discharge and groundwater level. We will derive numerical model of the effect of external stress field upon the fluctuations of crustal fluids. The residual anomalies will be statistically evaluated with respect to the local seismicity and passage of seismic waves from distant earthquakes.