The article presents a statistical analysis of the alteration of coefficients, which characterize the unsinusoidality and unsymmetry of the feed voltage and the utilized current in the electrical power supply systems of private housing projects (PHP). It is shown that, depending on the time of day, we can single out three characteristical periods in the daily schedule of the power, consumed by the private housing projects’ current-using equipment. The experiments have proved that the coefficients alteration refers to random processes with the pronounced trend and harmonic components. By means of calculation the regular it ies of random processes’ numerical characteristic salterations were received in time function for each characteristical period. Based on the seformulas, the most probable values of the coefficients are determined, with account of 5% annual loads growth. These values allow evaluating the power waste in private housing projects’power supply systems and select the engineering solutions for their reduction.