The article considers the possible pathways for tritium release from the water area of industrial reservoirs into the atmosphere under normal operating conditions at the facilities holding special (non-removable) radioactive waste generated due to the implementation of the state nuclear weapons program and the state defense order. The paper provides a list ranking each potential pathway of atmospheric air contamination with tritium above the water area of industrial reservoirs and evaluates the degree of its significance. The study demonstrates that it is the water evaporation from the surface of the reservoirs that most significantly contributes to the contamination (at least 99.99 % of the totally released tritium), while the total contribution of water aerosol droplet entrainment and tritium-containing methane emission is negligible (does not exceed 0.006 %).