Shocking a Well to Remove Coliform Bacteria

If you are buying a home with a well system and not public water you should absolutely be doing a water quality test.  It is best to test the water during the due diligence period you have as a buyer so that if anything comes up in the test results you will have time to consider your options and work out a solution if there is a problem.  Filtration systems can be expensive depending on what you need to remove.

The most common water quality issue that I encounter during the Home Inspection process is Coliform Bacteria.  Coliform is a required test for VA (Veteran Affairs) mortgage loan.  If Coliform is present in a home being bought with this type of loan it will need to be removed prior to purchase.

Coliform bacteria is referred to as an “indicator” organism.  Not all Coliform will carry diseases but they can indicate the presence of other bacteria and viruses that can cause illnesses, such as E. Coli.

If your water test comes back with Coliform present you will want to treat your well system.  This can be done by installing a whole house Chlorination System, Open Air Chlorination System or a UV filtration system.  Each home is different and a water quality and filtration professional should be consulted before investing in a system by yourself. 

If a filtration system is out of your price range another option is “Shocking” the well.  This is a process that involves putting a bleach solution down the well and flushing out the system.  There is a chance that the bacteria can return and you should test your water regularly if you do not have a filtration system in place.

If you are a home buyer and your potential home has coliform present you will want to have a professional shock the well.  Unless you plan on doing it yourself.  You do not want the current homeowners to shock the well on their own.  They may have a friend do it that doesn’t have any experience or know what to do.  They also may not even do it at all and tell you that they did.  I bring up this possibility because I have seen it before.  If you are going to have the sellers correct the issue make sure that you get receipts from a professional well company and follow up with another test to ensure the bacteria is gone.

Here is a basic guideline on shocking a well.  Keep in mind that every system is different and may need different procedures.

  • A typical solution for shocking a well requires 2 cups bleach and 10 gallons of water.
  • Dump the solution into your well.
  • Run a hose from the home to the well and run the water into the well to promote mixing of the solution. When you smell bleach coming out of the hose, shut it off.
  • Allow the well to sit for a few hours.
  • Run the exterior hoses away from the home and any plants and vegetation.
  • Run all the interior faucets and flush the toilets.
  • The flushing process can take a few hours or repeated flushing over a few day.
  • You may see brown water coming out of the faucets during this process.  This is common and is from sediment breaking up from the bleach solution.  Keep running the water and it should work itself out.
  • When you no longer smell bleach at the faucets you should be all set.  Chlorine test strips can also be used.
  • You should re-test your water about a week after shocking to ensure the bacteria is removed.

During the shocking process you should NOT use your water supply.  Here are some other things that you should NOT do during this process:

  • Drink the water
  • Shower
  • Give water to your pets
  • Water your plants
  • Do Laundry (the bleach may discolor your clothes and the rust deposits may stain your clothes)

Like any issue found during a Home Inspection, Coliform bacteria is easily fixed if handled properly.  If shocked properly the water may remain clean for a long time or it may not.  Most experts will advise that you test your well water once a year, while some say every other year.  If you have a shallow dug well you may want to test your water twice a year or more.  Especially if you live a quarter mile from a dairy farm with 100 cows.

 

I have also seen coliform form inside of a water softener brine tank.  The salt had not been filled and the tank had filled up with water which had a nice thick layer of growth on top of it.  A plumbing cross connection can also back flow waste water back into the system causing contamination.

There are many different ways that Coliform and other bacterias can enter your water supply and several different ways to treat it.  Obviously a high quality filtration system is the ideal solution but if that is not in the budget than hopefully a bottle of bleach is and you can clean your system.

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