This paper proposes a novel method to estimate the influence of domestic consumers on power quality, namely harmonic pollution, using fuzzy logic. Comparing the conventional measurement approach, the proposed fuzzy logic method is simpler and time saving. The fuzzy logic system used to quantify the impact on harmonic distortion, contains several modules: the fuzzifier, database, base rule and defuzzifier. The fuzzy system uses the Mandami type rule structure and linguistic fuzzy approach. The fuzzy sets were developed considering the domestic consumers' electrical apparatus (electrical lamps and appliances). Thus the linguistic variables were used to implement the behavior of these loads working together.