Fresh Water Plumbing System

A SUGGESTED METHOD OF DISINFECTION

Perform the following steps in the order indicated:
a. Flush entire system thoroughly by allowing potable water to flow through it;
b. Drain system completely;
c. Fill entire system with a chlorine solution having a strength of at least 100 parts per million, and allow to
stand for one (1) hour. Shorter periods will require greater concentrations of chlorine solution. See Table I
d. Drain chlorine solution from entire system;
e. Flush entire system thoroughly with potable water;
f. Fill system with potable water.
Table I shows how much disinfecting agent is required to make up various quantities of 100 parts per million chlorine
solution.

TABLE I – CHLORINE CONCENTRATIONS
Amount of chlorine compound required for 100 ppm solution

*NOTE: This table contains information taken from the Handbook on Sanitation of Vessel Water Points,
Public Health Service Publication No. 274 – Reprinted June 1963.