Distilled water is not supposed to contain > 5μg of chlorides and if it does, distillation is unsuccessful, and a repeat is needed. The quantification of chlorides post purification of reagent grade water though serves to illustrate the success of purification, has also been used in this study to illustrate nearness to success. A total of 50 registered Clinical Chemistry Laboratories in Lagos Mainland of Lagos Nigeria were recruited in this cross sectional study, their reagent grade water sampled and tested for chlorides using spectrophotometric technique. A questionnaire was also administered to ascertain the Laboratories’ headship. In this study, significant amount of chloride was detected in all reagent water tested with concentration range of 0.055mg/L - 38.760mg/L. Comparing the pathologists-headed laboratories with Scientists-headed laboratories shows that there is no statistically significant difference in the outcome of water purification at 95% confidence interval, p = 0.05, calculated t = 0.499, and critical value = 2.000. There is no significant influence on the outcome of reagent water purification by the headship of Clinical Chemistry laboratories.