What is all of this I hear about bacteria, wells and drinking water?
Following the 1993 flood of the nine states in the Upper Mississippi River Basin, the federal Centers for Disease Control and Prevention (CDC) provided a combined total of $1 million to assess the impact of the flood on water quality in private household wells. In some states, samples were taken from households that had flooded wells, in addition to households where the well was not flooded. Some households from both sets were found to have high total coliform bacteria levels. There were detections of E . coli bacteria in some samples taken from households with private wells. Preliminary data released from this study found approximately 41 percent of the water samples taken from private water distribution systems served by wells had total coliform bacteria present.

What are coliform bacteria?
Coliform bacteria originate as organisms in soil or vegetation and in the intestinal tract of warm-blooded animals (fecal coli) . This group of bacteria has long been the preferred indicator of the contamination of water and possible presence of intestinal parasites and pathogens. The coliform bacteria are relatively simple to identify, are present in much larger numbers than the more dangerous pathogens and react to the natural environment and treatment processes in a manner and degree similar to pathoge ns. Thus by observing coliform bacteria the increase or decrease of many pathogenic bacteria can be estimated.

Where are they found?
The many sources of bacterial pollution include runoff from woodlands, pastures and feedlots; septic tanks and sewage plants; and animals and wildfowl. Domestic animals contribute heavily to the bacterial population. Many coliform bacteria enter natural streams by direct deposition of waste in the water and the runoff from areas with high concentrations of animals or humans.

How do coliforms enter a water system?
The most likely sources are where the water is used. The spigot and sink, or unclean containers. A really common source is backflow from a contaminated source, a sink-top carbon filter, bucket of water or puddle at the end of a hose, or due to reduced pressure or suction in long water lines, drawing in soil water at joints.

Is the air gap for backwash or reverse osmosis concentrate sufficient to prevent backflow? Check for corroded water lines. Have an experienced plumber check these possibilities. The well construction itself should be examined. If the well top is buried, in a pit, or submerged (or you can't find it at all), chances are it leaks and introduces poor quality water. Older wells may not have been sealed properly or may be corroded. Other possibilities include leaking well caps or seals, leaking pitless adapters, or water line leaks. Poor fitting or damaged well caps permit small animals, insects, etc. to crawl into the top of the well. As they die and fall into the water, they decomp ose and may contribute coliform bacteria. The well pump should be well below the pumping water level if possible, and the water in the casing regularly flushed out. Make sure on-site wastewater treatment systems are properly designed, maintained, and functioning properly. Have a person experienced with these systems check it out.

Will coliform bacteria make us sick?
Maybe, maybe not. Coliforms are not one kind of bacteria, but many. Coliforms are defined by what they do: They grow on the sugar lactose (the same as found in milk), and have enzymes that help them use this sugar. Most coliforms are harmless residents of soil and will not make people sick. Some strains of E. coli, the most common fecal coliform bacterium (mostly living in animal fecal material), may be pathogens. Some found in food have been lethal. Their presence should be taken very seriously. Your immune system also determines whether or not you will become ill. People become accustomed to the natural bacteria in their water- (guests used to other water may have some discomfort or diarrhea. lmmunocompromised individuals may become ill under circumstances where people with normal immune systems would not, and should be very careful of the water they drink.

How do coliform bacteria survive?
Bacteria require a food source and warm, moist conditions for maximum survival. Although, once in the water the coliform bacteria begin to die, they are most likely to survive in deep, slow moving, heavily polluted waters that lack dissolved oxygen. The survival of coliform bacteria in soils depends on the soil's characteristics. Survival is much less likely in well-aerated soils. However, several other factors must be considered. For example, a sandy soil may be well aerated and have a low bacterial survival rate; however, if the depth to ground water is small and the water flow rate through the soil is fast, the bacterial contamination of the ground water may be high. In contrast, a heavy soil with slow water percolation rate and long distance to ground water will have a higher bacterial survival rate than the aerated sand. However, the long period of flow may allow enough time for the water to be filtered before it enters the ground water.

Why do they test for coliform bacteria?
While most coliforms are not pathogens, they serve as indicators of the microbial quality of water. Public health officials have tested for total coliform bacteria and fecal coliform bacteria for most of this century as a way of checking the quality of water Pathogens, the bacteria, protozoa, and viruses that make people sick, can be rare and difficult to detect even if they are present in the water. Total coliforms are indicators and are more common and easy to grow. Testing for them provides a margin o f safety. Pathogens may not be present if coliforms are. but it is time to look for problems just in case. Total coliforms are mostly natural residents of soil and water. Fecal coliforms are those that are usually found in the fecal material of animals. Their presence usually means that the water may be contaminated by sewage effluent. Finding the source of the problem and correcting it is very important.

If I have bacteria in my well, where do they come from?
Many experts in public health and water supply used to think that the subsurface was some kind of giant filter that trapped microorganisms before they could get to ground water, resulting in an effectively sterile water resource. We now know that many types of bacteria are native or adapted to saturated sediments and rock, and are indeed present in significant numbers in most water supply aquifers, even deep formations. Given time and a route (and soil and rock provide plenty of both), bacteria will migra te into and take up housekeeping in an aquifer. The environment is really rather nice -- quiet, lots of surface area, often adequate carbon sources, and moderate temperatures with little environmental change. Drillers and pump installers/servicers can also introduce microorganisms during their activities, but should not be considered the primary source of native microorganisms. There is no practical way at present to say for certain what is the source in any one well -- maybe someday, but not yet. "Non-native" coliform bacteria, or "protozoa" of potential health concern such as Giardia and Cryptosporidium are most likely introduced from the surface.

If my neighbor has coliforms in her water, will we get them in ours?
It depends on the source in your neighbor's water supply (see sources possibilities). It is common for contaminated and uncontaminated wells to be very close by. The reason is that most bacterial problems happen right at the well or after the water leaves the well.

Where else could bacteria come from?
Don't always blame the water first. Who sampled the water and how? How sanitary are your practices in food handling, personal hygiene, etc.). Do children wash regularly? While uncomfortable and personal subjects to some, these are more likely routes for contamination than the water itself.

If my well has bacteria, should we drink bottled water?
If you have unsafe levels of coliform bacteria you should obtain an alternative source of drinking and cooking water until the problem is solved. Don't neglect to solve the problem. Most bottled waters are not free of bacteria, but they should be free of coliforms. In the U.S., the Food and Drug Administration administers commercial bottled water quality. The source (bottler) should be able to give you information on the quality of the batch of bottled water you are using. Another source is water hauled from a nearby public water source that is tested to be safe for drinking. It is important that water jugs or tanks used to haul water are themselves very clean and free of coliform bacteria or chemicals.

If some people in our area have wells contaminated by bacteria, should we try to hook into public water?
Generally, area-wide coliform contamination is very rare. Usually the problem is at the wells or drinking water source, or may be due to faulty waste disposal on vulnerable land (shallow bedrock, for example). Look to your own source. If the cost of upgrade, property values, etc. exceed the cost of hooking to public water (seldom the case), then hook up. Also, if your ground water source is poor in quantity or quality, and solutions are too expensive or too much trouble, then hook up. Do not accept reason ing from neighbors or water districts that if some wells are contaminated, they all are, or that the only solution to low yields or poor quality are municipal water.

What's the difference between chloroform and coliform?
These are words that sound very familiar. Chloroform is a form of chlorinated organic chemical, a VOC, and coliform describes a group of bacteria that grow on certain types of growth media, or cause a color change when incubated that tells the analyst that these bacteria are present.

If my water is clear and smells OK, is it safe?
You cannot directly smell unsafe bacteria or protozoa. They can only be detected using tests designed for the purpose. You should check your water quality regularly. Some sources of odors are bacteria or septic, or the presence of chemicals. It is a good idea to take your nose seriously. Have the water tested.

What if my water is brown, or black, or smells bad?
The water may not be unsafe to drink, but you should test just in case. Also test for "iron bacteria" or biofouling-, iron, manganese, and sulfur Water treatment methods are available to provide clear, odor-free water. Check with several water treatment professionals for options.

What can be done?
The control of coliform bacteria is best accomplished through waste treatment and disposal methods that reduce bacterial survival. Proper site selection for rural on-site waste disposal systems provides protection through bacterial filtration in the soil. Bacteria are reduced through urban and rural storm water management systems which reduce runoff rates and volumes and maximize natural filtering processes.

What steps can be taken to determine whether you have a contamination problem?
A sanitary survey is the best way to determine private water system vulnerability. Vulnerable wells could include those with inadequate setback distances from potential sources of contamination (such as septics), inadequate well construction, and high flow hydrogeologies.

Siting wells in locations not vulnerable to pathogens.

• Horizontal and vertical setback distances from sources of fecal contamination to a well.
• Hydrogeological factors:
• Depth of unsaturated zone
• Confining layers
• Fractured and porous soils
• Land use patterns
• Ensure protection of the distribution system.
• Well construction to codes
• Cross-connection control
• Backflow prevention
• Age of the Well and Its Components
• Maintenance of the Well and Its Components

Changes in taste, odor or turbidity may be signals something has changed. Have your water tested by a qualified laboratory annually, when work is done to your system, or when there is any change in taste, odor or appearance. Water labs are listed in your phone book under "Water Testing" or "Laboratories."

How do we prevent this from happening again?
If possible, do whatever it takes to correct the problem in your existing system If necessary, install a new well and water inlet system, bringing it up to your state's code and good industry practice. Hire experienced water well drillers who are licensed in your state, and come recommended to you. Look for- quality, not price first.

When you are concerned about a water problem, what do you do?
Have your water tested by a qualified laboratory. Your local health department is typically the first stop. They will either do a free or inexpensive test for the presence of bacteria, or refer you to a qualified laboratory. To test for other substances, such as metals or chemicals, a more extensive and expensive sampling and testing program would have to be conducted. Independent laboratories will probably be required. They are listed in your phone book under "Water Testing" or "Laboratories."

Who does the homeowner contact locally?
Again, your first stop is your local health department. Explain to them your concerns. Another option is to have your water tested by a qualified laboratory. Additionally, you should have your complete water supply system annually inspected by competent water supply professionals, such as a ground water contractor. Further, your water supply should be tested annually for bacteria and anything else of concern to you, even if you do not perceive a change in your water.

Should I have my water tested?
The question of whether or not to have your water tested is a serious one that concerns the health of you and your family. Your water should be safe to drink and acceptable for all other household uses. Not everyone needs to test their water and it is impractical and unnecessary to test for all possible contaminants. If you obtain drinking water from your own well, you alone are responsible for assuring that is safe. For this reason, routine testing for a few of the most common contaminants is highly recommended. Even if you currently have a safe, pure water supply, annual testing can be valuable because it establishes a record of water quality. This record can be helpful in solving any future problems and in obtaining compensation if someone damages your water supply.

When should I test my water and what for?
The total coliform (TC) test that is usually mandated as a standard of "safe" water supply is a place to start. It is used to detect indicators of possible surface contact and therefore potential contamination. If the test is not run regularly, the time to start is now. The TC test will not detect the large majority of biofouling organisms or even most bacteria in a well. Note 1: It is not uncommon for wells showing no coliforms to have very large bacterial populations. Note 2: Some "native" bacteria will cause a "positive" coliform reaction in the ONPG (e.g., Coliert) total coliform test, but take any positive as a reason to look for possible problems.

Once each year test for coliform bacteria, nitrate, pH and total dissolved solids. It is best to do this during the spring or summer following a rainy period. These tests should also be conducted after repairing or replacing an old well, pump or pipes, and after installing a new well or pump. You may also wish to test during the following circumstances:

• If family members or house guests have recurrent incidents of gastrointestinal illness.
• If an infant is living in the home.
• If you are buying a home and wish to assess the safety and quality of the existing water supply.
• If you wish to monitor the efficiency and performance of home water treatment equipment.
• If you notice a change in the taste, smell, or appearance of the water.

Where can I have my water tested?
Private testing laboratories are listed in the yellow pages of the telephone book. Make sure they are certified by your state's health department. County and state health laboratories, departments of health, and local hospital laboratories often offer water testing services. University laboratories. Local environmental consulting or engineering firms may also test water.

How should a water sample be collected?
Most testing laboratories or services supply their own sample containers. Use the containers provided and carefully follow the instructions given for collecting, preserving and handling water samples. Samples for coliform bacteria testing must be collected using sterile containers and under sterile conditions. Some procedures require that water runs from an inside tap for several minutes before filling the sample containers. Other instructions ask you to collect samples in the morning after water has be en confined in the pipes overnight. Laboratories may sometimes send a trained technician to collect the sample or to analyze the sample directly in your home.

What types of treatment devices will make the water safe for consumption?
If treatment is necessary, there are a number of ways of addressing bacteriological concerns. Disinfection is the removal of infectious agents. Disinfection should not be confused with sterilization, which is the complete inactivation of living material. Water and wastewater disinfectants are potent biocides. The disinfectant concentration and contact time are the prime factors in the inactivation of a microorganisms. The product of the concentration and contact time for a specified level of kill (99%) , provides a useful term to compare disinfectants and factors affecting microbial inactivation. The contact times for each disinfectant are variable.

Biological contaminants are most effectively eliminated through chlorine disinfection, filtration, ultraviolet irradiation, and ozonation. All methods must be properly designed for the intended use and properly maintained. Additionally, bacterial analysis of the treated water must be made with sufficient frequency to ensure adequate treatment.

A disinfectant should be effective on many types of pathogens regardless of their quantity and it should be able to kill all pathogens within a reasonable retention time. The chemical should also be safe and easy to handle and it should not make the water toxic or unpalatable. In addition, the concentration of disinfectant in the water should be easy to monitor and the disinfection should provide residual protection against possible recontamination. Lastly, the disinfectant should be readily available at a reasonable cost.

Disinfectant dispersing equipment should also fill several requirements. The equipment should be automatic, require minimal maintenance, and treat all water entering the home. It should also be fail-safe so that no one can unknowingly use or consume untreated water.

Treatment methods include:

• Filtration
• Chlorination
• Ultraviolet irradiation
• Ozonation
• Silver treatment
• Iodination
• Pasteurization

All of these methods require proper maintenance, just as the well and the rest of the water system require regular and proper maintenance and service by a qualified professional.

How common are water problems?
"Pure" water does not exist - all natural water contains some gases and minerals. All natural waters, regardless of their source (surface or ground water), are likely to contain some microbial organisms. A few cause disease; some impart taste, odor, or turbidity to the water; others are beneficial; and the rest are of little interest.

The acceptability or desirability for the presence of these materials in water is usually a matter of individual preferences. Many people develop tolerances for drinking water of poor taste, odor or appearance, and they believe their water supplies do not need treatment. They should have their water supply tested every year or after well and/or pump service. If a water quality problem is present, it can usually be remedied with the appropriate water treatment equipment. Changes in taste, odor, or tur bidity (cloudiness) of the water may be the first signals of a water problem.

Most water bacteria are harmless, and many are actually beneficial. They consume organic debris, thereby reducing the water's chemical oxygen demand; prolong the useful life of filters; and destroy some foul tastes, odors, and colors. In addition, some produce by-products which kill or inhibit growth of some pathogens. Since pathogens are usually less numerous and less hardy in water than are other bacteria, their survival can be decreased by ordinary competition for food with more vigorous organisms.

Disease may be transmitted by the consumption of contaminated water and shellfish or close-contact recreation. The human pathogens of major concern in drinking water and shellfish consumption follow the anal-oral route of transmission. The pathogen must enter the host through an appropriate portal, overcome the host defenses, and proliferate to a sufficient degree to cause symptoms of the disease. This contamination results from human and animal fecal matter migrating from surface deposition or from se ptic systems or leaking sewer lines.

Are people getting sick from drinking water?
The Centers for Disease Control and Prevention issues an annual survey of foodborne and waterborne disease outbreaks. For the two-year period 1991-1992, 17 states and territories reported 34 outbreaks associated with water intended for drinking. The outbreaks caused an estimated 17,464 persons to become ill, or about 0.0076 percent of the U.S. resident population. Ground water supplied from a well was responsible for only 23 percent of the persons who became ill. Surface water sources, or a spring, were responsible for 77 percent of the illnesses.

However, some researchers contend we do not currently have a valid, quantitative understanding of the magnitude of waterborne disease in the U.S. One researcher contends that about 20 to 25 percent of ground water sources are contaminated with pathogenic viruses or bacteria.

What about bacteria in public water systems?
About 40,000 of the 210,000 ground water-supplied public water systems reporting via the Federal Reporting Data System have had microbial violations indicating bacterial presence in their ground water, wells or distribution systems during the last five years. Smaller systems and noncommunity systems tend toward violations from source water contamination. Contamination of distribution systems results from cross contamination and backflow events and from bacterial growth within a system. Some septic system s, displaced by rising ground water pressure or flooded, may become hydraulically connected to wells. They are the most frequently reported causes of contamination in ground water disease outbreaks associated with the consumption of untreated ground water in the U.S. Other sources are animal feedlots, and the like.

What types of illnesses are caused by bacteria in drinking water?
Pathogenic (disease-producing) organisms occurring in water range from ultra-small viruses to microscopic bacteria to relatively large protozoa (cysts). Basically, three types of pathogenic organisms can affect the safety of water: bacteria, viruses, and protozoa. Bacteriologic and protozoic pathogens are known to cause typhoid, dysentery, cholera, and some types of gastroenteritis. Conventional wisdom is that contamination of ground water with protozoa indicates surface water influence. Viruses accoun t for more than 100 human maladies including polio, infectious hepatitis, and some forms of gastroenteritis. In general, viruses are more poisonous and more resistant to disinfection than bacteria.

How is contamination limited during drilling and pump service?
Despite the fact that the most likely source of a microbial population in a well is the aquifer around it, drillers and pump contractors are widely accused of transporting the bacteria about. Drilling and well service cannot be sterile, but some steps are available to minimize the possibility of such transport. Any individual following the steps listed here should be credited with doing all that is feasible to avoid contamination.

(1) Become familiar with local problem wells.

(2) Minimize practices that introduce or harbor bacteria during drilling, jetting development, and hydrofracturing. Repeat: Drilling and well completion are not sterile pursuits and never will be. Like anything else in the environment, the rig, tools, etc. are covered with bacteria, even when clean.

(3) Develop thoroughly after drilling and always chlorinate after development or after pump service. Well development removes drilling damage and mud that hide microorganisms, and also provides more effective well intake area to minimize the effects of biological buildup when it happens.

(4) Always chlorinating after development or pump service to your state's recommendations (usually 100 ppm or so) minimizes contamination due to drilling and service activity.

(5) Keep tools as clean as possible. After well development or redevelopment, drillers should clean tools thoroughly (to the clean steel). Keep casing, riser pipe, pumps, etc. off the ground and out of the mud. Never reinstall any pipe with any encrustation, mud, or film of any kind without thorough cleaning and chlorination.

(6) Always have proper water analyses run on a new well whenever it is serviced. These include total coliform bacteria and chemical parameters useful to both health and safety and general water quality (nitrates, hardness, iron, etc.). Proper sampling is crucial. If sulfur or iron bacteria are a problem, tests can be run to analyze these as well.

What requirements do public water systems have for dealing with bacteria?
All community public water systesms, as well as non-community public water systems (public systems that does not serve a residential population) must submit samples for coliform bacteria testing on a regular monthly basis. Failure to submit samples, meet the maximum contaminant level (MCL) and report non-compliance are all violations of the rule. However, remember that the sample is probably not taken inside your home. Parts of your own household plumbing may be a source of bacteria in your own drinking water.

The maximum contaminant level is based on the presence or absence of total coliforms in a sample (the old maximum contaminant level was based on an estimate of coliform density). A very small water system may have one coliform positive sample per month and still remain in compliance with the regulation.

What requirements do private water systems have?
Each state may have its own unique requirements for disinfection and water quality monitoring. Check with your state water agency to determine what is required in your state.

How do I find a qualified ground water contractor?
Many qualified ground water contractors, usually known as water well drillers and well pump installers, are listed in your local phone directory. Many states require either registration or licensing of contractors. Always make certain your contractor is properly registered or licensed with your state.

The National Ground Water Association maintains a voluntary certification program for contractors. In fact, many states, but not all, use this program's exams for licensing purposes. For a list of contractors, including those voluntarily certified, contact the Association at 614-898-7791.

How do I find a qualified water treatment specialist?
You can find listings of water treatment specialists in your phone book under "Water Conditioning," or "Water Treatment." Be sure you speak about water treatment and not water conditioning, such as softening.

What is the "iron bacteria" problem?
Better described as iron biofouling, the problem popularly known as "iron bacteria" is both complex and widespread. Iron and other biofouling consists of biofilms which include living and dead bacteria, their sheaths, stalks, secretions and other leavings, and embedded metal hydroxide particles "Iron bacteria" is one type of biofouling among several, including the characteristic white sulfur slime of sulfur springs. Manganese and even aluminum biofouling is also found in ground water systems.

These biofilms are natural and usually harmless. Natural iron biofouling often acts as a preliminary iron filter in wells and therefore can serve a positive function as well. They can be a nuisance, however. Generally, iron biofouling is the cause of iron build up in wells and pipes. Bacterial iron may build up quickly compared to mineral encrustation. In addition to causing problems in wells, the bacteria may colonize tanks and water treatment devices, as well as spring outfalls. Iron biofouling ge nerally causes side effects such slight and intermittent sulfide odor, breakthroughs of red water, and pitting-type corrosion of steel and iron.

Features of water systems may aggravate certain symptoms. These include: inappropriate well, filter, or plumbing design or material choice, or construction, poor choices in water treatment, and well use patterns.

How does biofouling and its control affect water treatment?
Bacteria, oxidized iron and manganese, sulfur and other slimy products are slow killers of resin beds and many iron/manganese removal and filtration devices. Biofilms overwhelm and defeat carbon filters -- even "bacteriostatic" types and bactericidal resins. They also attack or plug reverse osmosis membranes and cartridge filters.

Aeration-type or redox-media, backwashable iron filters tolerate biofouling pretty well, and these make good screening, filters for most water systems. small or large. They have to be designed and maintained well, taking the biofouling in consideration - including making sure the backwash is effective in removing most of the accumulated iron debris in the filter bed periodically.

When is the best time to clean up a biofouling problem such as iron bacteria?
The best time, obviously, is as early as possible before real damage occurs and treatment methods are most effective. This is usually long before noticeable plugging, loss of efficiency, and other gross symptoms become noticeable. The key to catching a growth before it causes problems is preventive monitoring, starting when the well is new or at any favorable point. This advice is also for private water and monitoring wells.