Both of these records should be prepared in duplicate, and both should be summarized at the end of the month. The original should be retained on file and the carbon copy forwarded to the district public works officer not later than the tenth of the following month. Activity files should include records of the current and two preceding years.

Keep forms clean, concise, and hand print with a pencil or a pen so as not to smear. Information on forms must be understandable and legible for future reference. Constant reference is made to the data as a means of checking and increasing plant efficiency. It provides a control measure to obtain the maximum efficiency of operation and to SAVE, not WASTE, chemicals used in water treatment.

Q16. Why is water analysis, through water testing, done during treatment?

Q17. What are the two types of water tests used to determine chlorine residual?

Q18. On the pH scale, what does a reading of 7 indicate?

Q19. You are performinga chloride test and have used 2.5 ml of AgNo₃ in a 25 ml water sample . What will the ppm of chloride be?

Q20. What is the purpose of the jar test?