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Sources of Chlorine in Drinking Water - a guide to chlorine sources and what to do about them InspectAPedia®  -     What are the possible sources of chlorine in drinking water? How do we remove un-wanted chlorine odors in drinking water How to Avoid Water Test & Septic Test Cheating Problems What to Do About Questionable Water Test Results

This article explains why people might do something that prevents you from obtaining an accurate water test, how to detect this bad behavior, and what to do about it. Cheating on drinking water tests may come as a surprise to most folks - who would do such a thing, and why? Also see Choices of Water Tests & Fees: A Summary of Types of Water Tests, Degrees of Comprehensive Water Testing, Details of Water Test Parameters. and Water Testing Advice based on information from Cornell University of Maryland with extensive edits, text additions, and additional references.

Sources of chlorine in drinking water from private wells and public water supplies

Chlorine in private well water? From what cause or what source do we find chlorine in water? One would not expect to find chlorine in well water from a private residence except for a few conditions, most of which indicate a concern for the sanitation of the water supply.

• Chlorine from municipal water supply: If your water smells like chlorine, first let's find out if your water is supplied by a private well or by a municipal water system and it is chlorine that you smell. Chlorine is quite volatile and doesn't stick around in water - if you run water from a tap into a pitcher and let it sit, the chlorine will dissipate pretty quickly. People who want to avoid chlorine in their water can install a treatment system such as charcoal filtering to remove it.
  
  Municipal water supplied: The water may not be from a private well - you may have misunderstood or been misinformed. Community water supplies often contain chlorinated water. Old wells and complete water supply systems are sometimes left in place after a home is connected to a municipal water supply.
  
  Most municipalities are careful to be certain that the homeowner has no physical plumbing connections between the well water system and the municipal system, as they don't want to risk back-contamination of their supply. An old well might be kept working, for example, to water laws or wash cars.
  
  Follow the pipes in your building to the point where water service is provided to be sure you know where water is entering and from what source it arrives.

• Well Water Chlorinator may be Installed: (photo at left) The water supply may be known to be unsanitary, and a chlorine injection system may be installed. If post-processing of the chlorinated water is not properly adjusted, odors of chlorine may be present at fixtures, or may be detected by testing with a Hach or similar test kit.
  
  If a drinking water treatment system is installed, you can find it, make sure it's working, test the well to determine what's really needed, and be sure that the treatment system is properly maintained. If your home water smells like chlorine and you have a chlorinator installed for water disinfection, make sure the equipment is properly adjusted.
• If someone has just shocked or sanitized the water well to try to correct a bacteria problem (a step which is ineffective if there is a persistent bacteria source - See WELL CHLORINATION SHOCKING PROCEDURE) it is possible that you have not run enough water to flush out all of that chlorine (bleach).
• Recent well shock treatment after work on the well, well piping, or submersible well pump: the well may have been shocked as normal good procedure following work on and removal/replacement of a submersible pump or piping in the well itself. Chlorine from this or any well shock treatment is left in place (typically for 24 hours at the proper concentration of chlorine), then flushed from the well quite thoroughly in order to avoid giving the occupants chlorine to drink or to accidentally bleach their clothes.
  
• If you have just sanitized your water softener it is possible that you have not run enough water to flush out all of that chlorine (bleach).
  
  So unless a well shock for a legitimate reason is virtually in process at the time of an independent test that detects chlorine, we'd suspect something darker, discussed in the next bullet. [Thanks to SGP Rich for this tip -- DJF 5.2006]
  
• Recent well shock treatment to Hide a Problem: The well supplying the building may have been recently "shocked" with bleach either in a attempt (questionable) to correct a known bacterial contamination problem, or in a attempt to disguise a known contamination situation (highly dishonest and dangerous).
• If readers know of other reasons why we'd find chlorine in a private water supply, please let me know.

As we mention in the list above, people might shock a well or install a chlorine treatment system for sanitation or to remove an odor from water - for a legitimate reason. Finding out if this is the case is one step in determining if the building piping or well casing have become soiled and contaminated or after actually doing work on the well pump or piping in the well itself.

Shocking a well with bleach will have only a temporary effect in reducing the bacteria level in water if there is a persistent source of contamination in the water supply.

We discuss this water problem diagnosis procedure in detail at Interpreting Drinking Water Test Results and Correcting Unsatisfactory Drinking Water and the details of well shocking with bleach are located there

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CHEATING ON WATER TESTS
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