Solving Bacteria Problems in Wells and Springs

This video discusses various steps homeowners can take to solve or treat bacteria problems in wells, springs and cisterns used for drinking water.
Solving Bacteria Problems in Wells and Springs - Videos


This video discusses various steps homeowners can take to solve or treat bacteria problems in wells, springs and cisterns used for drinking water. It includes how to interpret bacteria test results and re-testing is warranted to confirm results. Common sources of bacterial contamination are also described along with steps to remove these sources and disinfect wells with chlorine. Permanent treatment solutions like ultraviolet light systems are also explained in cases where the source of the contamination cannot be determined or removed.


  • Interpreting bacteria test results
  • Re-testing to confirm bacteria presence
  • Finding and removing sources of bacterial contamination
  • Checking well and spring construction as a possible source of bacteria
  • Shock chlorination to kill existing bacteria
  • Permanent treatment systems including chlorination and ultra-violet light.


Water wells, springs and cisterns Pond management Watershed management Water conservation Shale gas drilling and water Acid deposition

More by Bryan Swistock 

View Transcript

- [Instructor] Hi, I'm Bryan Swistock.

I'd like to take a few minutes to talk about how you can solve bacteria problems in your water well or spring.

Coliform bacteria and E. coli bacteria are the two most common water tests done on wells and springs, to determine their microbiological safety for drinking.

Total coliform bacteria are a large group of bacteria that are common in surface water, while E. coli bacteria come from the feces of animals or humans.

These two groups of bacteria are called indicator organisms because they indicate that a potential pathway exists for disease causing bacteria to enter the water supply.

Federal and state drinking water standards dictate that both bacteria groups should be absent from drinking water, because they can cause various gastrointestinal illnesses.

These illnesses are especially severe in children, elderly or visitors to the home who are not accustomed to the bacteria.

If you got your water tested through the Penn State water testing lab, you would have received a test report like this one.

The bacteria results show the number of each bacteria group that were found in 100 milliliters of water.

If no bacteria are found, the result is given as None detected, as is shown in this report.

A result of None detected means the water is safe to drink, while any number for either bacteria indicates unsafe drinking water.

Here's a different water test report showing a water supply that has a bacteria problem, with more than 201 colonies of coliform bacteria and 43 colonies of E. coli bacteria.

In this case, the homeowner should act to solve the problem.

A Penn State study of wells and springs found that both coliform bacteria and E. coli bacteria, were much more common in springs and shallow hand-dug wells and less common in deeper drilled wells.

Note that about 90 percent of springs had coliform bacteria, while only 33 percent of drilled wells had coliform.

If your test report shows that coliform bacteria or E. coli bacteria are present, let's talk about some steps you can take to solve the problem.

First, keep in mind that owners of private wells and springs, are not legally required to meet any drinking water standards.

Some homeowners, especially those with small, single-digit numbers of bacteria per 100 milliliters of water, choose to live with the risk of the illness.

While doing nothing is legal, it cannot be recommended.

It ignores the risk of illness, especially for visitors to your home who could hold you legally liable for waterborne illness.

A second consideration for resolving bacteria problems is to consider re-testing the water.

Bacteria tests are readily available and inexpensive, but should always be arranged with a state-accredited water testing lab, like the Penn State Agricultural Analytical Services Lab.

Re-testing can make sense, because it's easy to inadvertently contaminate a water sample during the sample collection.

Coliform bacteria, and even E. coli bacteria, can be present on your hands, countertops and faucets.

If you fail to collect the sample carefully using the instructions provided by the lab, it's possible that you contaminated the sample, resulting in the presence of bacteria that are not actually in your well or spring.

If you have any doubt about your sample collection procedure, you may want to spend the small amount of money to re-sample and confirm your original result before proceeding with more expensive and time-consuming solutions.

If you decide to re-sample, be sure to use sterile containers provided by the lab and follow the instructions carefully.

Deliver the sample to the lab as soon as possible, but always within 30 hours to ensure accurate results.

Once you are confident in your water test results, the next step for solving the issue is to look for obvious sources of bacterial contamination around your well or spring.

In this picture, a dog is tied to the well casing.

All sources of contamination, such as animals, septic systems and run-off should be at least 100 feet from the well casing or spring box, and preferably downhill.

Bacteria can also enter a well when work is done to the well.

In this picture, the submersible pump is laying on the yard, where it can easily pick up bacteria and contaminate the well when the pump is installed.

Any time work is done to the well, it should be disinfected with a shock chlorination process, which is described later in this video.

Flooding or surface water is another common cause for bacterial contamination of wells.

This picture shows a well on a floodplain, where surface water can easily enter the well.

Any time your well becomes flooded or muddy after a rainstorm, it will need disinfectant, to remove bacteria that almost certainly came with the high water.

A fourth step for solving bacteria problems is to examine your well or spring construction.

Here a bent well casing allows for openings under the well cap, to provide easy access for insects and small mammals.

Make sure your well casing extends above the ground surface and is in tact to prevent contamination.

If needed, new pieces of casing can be welded onto the existing casing to make necessary repairs.

Take a close look at your well cap.

Make sure it is tightly secured to the casing and is sealed to prevent insects and surface water from entering the well.

Standard well caps, with bolts that secure the cap to the casing, do not provide a watertight seal, and can be a common cause of bacteria problems.

If you have a standard well cap with bolts, consider replacing it with a sanitary or vermin-proof well cap, like the one shown here.

These caps have a rubber seal inside the cap which prevents insects and surface water from entering the well.

Also, check around your well casing to make sure that surface water is not collecting around the casing.

Most water wells in Pennsylvania, lack a grout seal, which is a cement-like material placed around the casing during the drilling process to prevent surface water from contaminating deeper groundwater by flowing downward along the casing.

Loose soil that is placed around the casing after drilling often compacts over time, into a space around the casing, leaving a low area which collects runoff.

If you notice a low area around the casing, use soil to grade it, to ensure that surface water flows away from the casing, rather than toward it.

Here's a well that has good construction to reduce the chances of bacterial contamination.

It has a casing above the ground, a sealed well cap, no polluting activities near the well, and a good ground slope around the casing to prevent surface water from entering the well.

If you have a spring, make sure that the spring box is sealed to prevent insects and animals form entering the water.

Even with all precautions, springs are notoriously difficult to keep clean from bacteria, and often need permanent treatment systems that are explained later in this video.

Up until now, we have discussed methods to try to prevent bacteria from entering wells and springs, a final option for solving bacteria problems is to install treatment, to kill bacteria as the water enters the home.

Shock chlorination is a temporary treatment method that can be used to kill bacteria that have entered the well during repairs, heavy rain, insects, or other nearby sources of contamination.

The effectiveness of shock chlorination assumes that the source of the original bacterial contamination has been found and stopped.

The step-by-step process, which must be followed carefully, involves pouring a chlorine/water mixture into the well, mixing it with a garden hose, running water to each faucet in the home until chlorine is smelled, letting it sit in the plumbing overnight, and then running the high-chlorine water to a waste area the next day.

The exact amount of chlorine to use and other details are explained on numerous online articles and videos about shock chlorination.

It will cause some temporary changes to the smell and appearance of the water, which will disrupt the normal use of the water for several days.

Even when done properly, research at Penn State has found that shock chlorination only has a 15 percent long-term success rate.

You should re-test the water approximately two weeks after the chlorine odor has dissipated, to determine its effectiveness, and again a few months later to determine long-term success.

Other treatment solutions include boiling, ozonation, ultraviolet light and chlorination.

Boiling is very effective, but is not a permanent solution and ozonation is extremely expensive for household-size units.

Ultraviolet light and chlorination are the most common approaches to bacteria treatment for wells and springs.

All bacteria treatment requires that the water be completely clear of sediment.

For this reason, cartridge style sediment filters are usually installed first, to remove all sediment and maximize the effectiveness of the disinfection treatment.

These cartridge filters typically need to be replaced every two to three months, or when water pressure begins to drop as the filter plugs.

UV treatment systems are the most common method for continuous bacterial disinfection treatment.

Their popularity stems from their small size, simplicity and effectiveness.

Water flows through a glass or quartz UV tube where a UV light bulb irradiates the water and inactivates the bacteria.

Properly sized and designed UV treatment systems can also be used for other parasites like giardia and cryptosporidium.

UV treatment does not add any chemicals, and the only maintenance is annual replacement of the light bulb.

A disadvantage of UV light is the lack of any residual treatment after the UV unit, meaning any contamination that occurs after the unit would not be disinfected.

High levels of iron, manganese or hardness in the water, can also interfere with the effectiveness of a UV treatment system.

In these cases, additional treatment with a water softener or oxidizing filter may be needed before the water enters the UV light.

In this picture, the water only had a slight sediment problem, which required the small blue cartridge sediment filter installed before the water enters the UV tube.

Another type of disinfection used in all public water supplies in the United States to disinfect water, is continuous chlorination.

On household wells and springs, small chlorine injection systems are available.

The feed pump injects chlorine from a solution tank before the pressure tank.

A larger retention tank is also installed, to make sure that the chlorine has plenty of time to kill bacteria before the water moves into the household plumbing.

If the resulting chlorine concentration is offensive, a carbon filter can be installed after the retention tank to remove the chlorine after it has done its job.

Bacterial contamination is one of the most common problems found in water wells and springs.

Thankfully, there are a wide variety of methods that can be used to solve bacteria problems, sometimes with very little effort.

By using one or more of the methods we discussed, you can ensure that your next water sample will be free of bacterial contamination.


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