This survey was carried out to investigate the temperature, pH value, nitrogen (ammonia, nitrite, nitrate), turbidity, color, chloride ion, $KMnO_4$ consumed, and hardness as chemical analysis of the tap water in Seoul city area during the period from September to Octobor, 1979, and to observe the differences among the values by the distance from the water purification plant and by the district supplied tap water from-the each water purification plant. The results obtained were as follows: 1) An average of the water temperature was $19.8pm 0.2circ$C. 2) An average of pH was $7.18pm 0.02$. The difference among each district was statistically significant (p<0.01), but it was not observed among each distance. 3) An average of turbidity was $1.25pm 0.12$ ppm. The difference among each district was highly significant (p<0.01), respectively, but not among each distance. 4) An average of color was $1.43pm 0.16$ ppm, and there were statistically significant differences by the distance and by the district (p<0.01). 5) An average of ammonia nitrogen was $0.022pm 0.005$ ppm. The differences among each distance, and district were statistically significant (P<0.01). 6) An average of nitrite nitrogen was $0.0050pm 0.0013$ ppm, and the difference among each distance was highly significant (p<0.01), respectively, and each district showed statistical significance (p<0.01). 7) An average of nitrate nitrogen was $0.82pm 0.08$ ppm. The difference among each district was significant (p<0.05), and each distance showed high significance (p<0.01). 8) An average of $KMnO_4$ consumed was $3.73pm 0.16$ ppm, and the difference among each district was significant (p<0.05), but it was not observed among each distance. 9) An average of chloride ion was $8.56pm 0.28$ ppm, and the difference among each district was higly significant (p<0.01), respectively, but it was not observed among each distance. 10) An average of hardness was $40.69pm 1.17$ ppm, and there was statistically significant difference by each district (P<0.01), but not by distance. 11) The interrelation between temperature and pH of the tap water revealed the negative correlation from the coefficient of it as showed r=-0.6073 and p<0.01. 12) Except water temperature, there were negative correlationships between pH and other water qualities. 13) Correlation coefficients of $KMnO_4$ comsumed and ammonia nitrogen, nitrite nitrogen were statistically significant but that of $KMnO_4$ consumed and nitrate nitrogen showed no statistical correlationship. 14) Ammonia nitrogen seems to have high correlationship with nitrite nitrogen(r= +0.6669), but not with nitrate nitrogen. 15) Nitrate nitrogen seems to have statistically significant correlationship with nitrite nitrogen (r=+0.4959), but not with ammonia nitrogen. 16) The interrelation between chloride ion and hardness of the tap water revealed positive correlation from the coefficient of it as showed as r=+0.4888 and p<0.01.