The concept of reliability-oriented maintenance of gas distribution networks is substantiated. Performed an analytical review of works of leading scientists in the field of the theory of gas supply of individual household. It has been established that the question of control and to prevent gas leaks remains relevant now. It is proved, that for engineering systems use gas for domestic purposes, also the greatest risk are low-intensity gas leaks, that hardly controlled by hardware due to accounting errors. An algorithm is presented for vulnerability assessment elements engineering gas supply systems for leaks. The mathematical model for the evaluation of measuring error of parametric parameter of gas flow in the system. The technique for monitoring the tightness of gas systems engineering with the rationale for selecting the method of evaluation of error results.