Background
We use the term organics to refer to a large category of natural contaminants that are related to the decomposition of natural organic matter, such as plants and trees. Sometimes organics are called tannins, lignins, or humins. Organics are a possible indicator of surface water intrusion. However a negative lab test for these items does not necessarily mean that surface water intrusion is not present; we rely on an evaluation of the symptoms (below) to determine the presence of organics. Surface water can reach a drilled well because a new vein has opened up, (sometimes related to blasting or the drilling of new wells in the area, or earth tremors), the casing seal is separated from the bedrock, or from a leak in the casing pipe. In rare cases organics are inevitable due to the local geology, but usually organics do not reach wells due to the length of casing inserted into the bedrock when the well is drilled.

Symptoms
You should suspect organics when:

• Water has a very unpleasant taste or odor, described as any of the following:
  • Wet bandaid or Rubber hose
  • Earthy, musty, swampy, septic or manure-like
  • Often the odor will stick to the skin and still be present long after showering.
  • The taste usually makes the water repugnant to drink.
  • Hydrogen sulfide (rotten egg smell) does not imply organics.
  • HOWEVER, beware because hydrogen sulfide can mask the taste or odor of organics. Give the hydrogen sulfide time to dissipate, then check for organics.
• Water changes with the season, or after a rain. For example, a yellow color, or higher incidence of iron occurs after a strong rain but dissipates as the weather becomes drier.
• Water test results vary greatly from one test to another.
• Water tests with extremely high manganese. (Manganese is found in the soil.)
• A plaque builds up where the water sits, for example in the toilet tank. This may actually peel or crack off.
• Existing water treatment has a difficult time removing iron or manganese, which may be bound up with the organics

Treatment
Any of the above symptoms imply that surface water intrusion is occurring. It does not prove that the well was improperly constructed; the surface water may be reaching the well due to local geologic conditions.

In either case, the customer is best served by first having the well evaluated to determine if water is recharging the well from a point likely to be fed by surface water. Many well drillers have special cameras and the ability to determine if a problem exists. If a source of the surface water is found, the well can often be sleeved to stop that source. Choosing the length of the sleeve or casing is difficult; in some cases a casing of several hundred feet has been necessary.

While organics can often be treated, it is very difficult to design a system that will be adequate to treat the possible range of water conditions. Water treatment often requires chlorination, filtration, dechlorination, softening, neutralization and drinking water treatment. This represents a system too complex for most homeowners.

Chlorinating water with heavy organics present will create trihalomethanes and halo acetic acids which are carcinogenic. These carcinogens are predominantly removed with the granular activated carbon dechlorinator, but the overall health of the treated water must be carefully considered when deciding to treat.

In some cases a new well is the best choice. If a new well is to be drilled, extra casing should be used to prevent the reoccurrence of the problem.