Quick Start Guide
Chapter 42: Drinking Water Safety

Program: Drinking Water Safety  
NEW 07/12
URL: http://www.lbl.gov/ehs/pub3000/CH42.html
Revision Record: http://www.lbl.gov/ehs/pub3000/Pub3000Changes.html

Who needs to know about these requirements?

The requirements of the Drinking Water Safety program apply to:

• Berkeley Lab employees, visitors, affiliates, and subcontractors

Whenever they:

• Use drinking-water systems or perform work pertaining to drinking-water systems at Berkeley Lab

Why?

If left unchecked, drinking-water systems can become contaminated beyond allowable levels. 
Contamination may:

• Affect taste
• Cause health effects

What you need to do if you suspect drinking water contamination:

• Contact Heather Madison, the EHS Drinking Water Safety Subject Matter Expert, ext. 7609

What you need to do if you are involved with a drinking-water system installation, modification, or repair:

Water systems must be isolated from the main water system and not put into service (excluding small jobs; see below) as potable water until the water is confirmed to be free of coliform bacteria. In all cases, the new water system must be thoroughly flushed (minimum of 10 minutes) before the system is released for service. See Work Process C, Disinfection of Water Systems, and Work Process D, Bacteria Testing.

• Underground piping systems. These must be disinfected with an aqueous solution of sodium hypochlorite or calcium hypochlorite having at least 5.25% available chlorine. See Appendix A, Disinfecting Domestic Water Systems, for procedure.
• Aboveground piping systems.These need not be disinfected as outlined above, though in all cases they must remain isolated from the main water system until coliform bacteria test results confirm the bacterium is absent. If coliform bacteria are present in the piping system, it must be disinfected following the Appendix A procedure.
• Individual parts, fixtures, isolation valves, pipes less than 5 feet long. These can be swabbed with full-strength bleach (5.25%) or soaked for at least 30 minutes in a 500 ppm chlorine solution.  Parts should then be thoroughly rinsed before putting into service. A coliform bacteria test is not necessary for this small-scale work.
• New piping installations. In drinking-water systems, new piping installations must be tested for coliform bacteria before they are approved for use for potable water unless the work is of a small scale, and provided the parts are individually disinfected (see above). Samples must be analyzed by the membrane-filtration method after a 24-hour incubation period in the pipes with chlorine-free water. See Appendix D, Sampling Procedure for Bacteria in Drinking Water, for details of the sampling procedure. Water-sample analysis must indicate that the water is free (i.e., none detected) of coliform bacteria. If it isn't, the piping must be disinfected again.

Where to find out more:

Berkeley Lab ESH Manual, Drinking Water Safety

Whom to contact for help:

• Heather Madison, the EHS Drinking Water Safety Subject Matter Expert, ext. 7609.