Maintaining My Well- Keeping Iron Bacteria at bay

Iron bacteria, while not a health hazard, are an incredibly common nuisance in water wells, and once you have it you will always have it. Iron bacteria use dissolved iron in the water as an energy source and leave slimy deposits of red iron hydrate as a by-product. I test my well water each year during the annual water clinic the Prince William Extension Office hosts and every few years for all primary and secondary pollutants under the safe drinking water act but, iron bacteria is not part of those suite of tests. The standard bacteria tests test for coliform and fecal bacteria and do not test for iron bacteria. However, about a decade ago I tested my well water for iron/reducing bacteria and found a significant level. There had appeared a number of symptoms that suggested its presence, so I looked.

Iron bacteria once introduced into the well will not get better. Instead continue to get worse ultimately binding up your pump and fouling the well. Iron bacteria can grow on pump intakes and screens openings causing plugging reducing the yield and efficiency of the well. In addition, the bacteria will make the water smell and taste vaguely unpleasant. A much earlier symptom is slime build up on the toilet tank flipper and in my case gross foam in the ATU tank.

Elevated levels of iron, manganese and sulfate in groundwater are an ideal media for iron bacteria to grow. Iron bacteria are present in soils and surface water in this area of Virginia and in many other parts of the country. Iron bacteria can be introduced into a well during drilling or repair. There are tests that can look for these micro-biologicals. National Testing Laboratories sells a mail in test for $69 plus shipping if you want to test your well. That is what I used.

It is common practice to regularly treat public supply wells to prevent biofilm buildup and mineral encrustation. Preventive maintenance is to chemically treat and flush the production well.  However, this has not been the practice in private water well, though now several state health departments and Canadian Provinces are recommending the regular chlorination of private wells to push back the iron bacteria.

The last time I heard Brad White a groundwater geologist from the Virginia Department of Environmental Quality Office of Ground Water Characterization give a talk on the work DEQ was doing in Fauquier County, he happened to mention that in every well he put a camera down he had observed iron bacteria.

From Penn State Extension: “As a water well ages, the rate at which water may be pumped tends to decrease.” Penn State attributes this decrease in performance of a well to incrustations and biofouling (with reducing bacteria) of well screens and rock fractures or borehole, saying: “In severe cases, the obstruction to flowing water can render the well useless. Major forms of incrustations can occur from build-up of calcium and magnesium salts, iron and manganese compounds, or plugging caused by slime producing iron bacteria or other similar organisms (bio-fouling).”

The Provincial Government of Alberta (Canada) says in describing iron bacteria: “This slime will coat the inside of the well casing, water piping and equipment, creating problems such as reduced well yield, restricted water flow and red staining of plumbing fixtures and laundry...” There are all sorts of odd problems that are caused by iron bacteria. Over time many wells develop these problems. These harmless bacteria can foul a well, damage pumps, stain plumbing fixtures, clog pipes, faucets, showerheads, and produce unpleasant tastes and odors in drinking water. Rarely is well water tested for iron bacteria. 

Private well owners typically try to treat the symptoms rather than the cause of the problem. Elimination of iron bacteria once a well is heavily infested can be difficult. Iron bacteria cannot be eliminated by most common water filtration methods or water softeners. Iron bacteria will foul that equipment.  However, though it is difficult to eliminate, it is actually very easy to control – just oxidize the heck out of the well. This is accomplished by chlorine shocking of the well with adequate chlorine concentration and several hours of mixing accomplished by recirculation.  

As recommended by Alberta, Pennsylvania and other states,  routine maintenance of a private water well should include regular chlorination to control biofouling of the well and maintain water quality. Personally, I chlorinate my own well on even number years (yes that includes this year) to prevent the buildup of a biofilm in my well and plumbing system and maintain the aesthetic quality of my water. I drain and flush the hot water heater annually to protect it from biofilm and mineral buildup and keep the temperature above 145 degrees to prevent the growth of reducing bacteria.  If you have treatment equipment like a water softener, you might want to consider chlorinating your well annually and treating your media to prevent a bio mat from forming in the media tanks.

There are so many things that regular chlorination will solve or prevent that you might want to consider it a regular part of home maintenance. Even if you do not chlorinate your well regularly, you should chlorinate your well when:

• the well is new
• the well has been repaired
• the well has been flooded
• the well exposed to bacterial contamination in another manner, such as a crack in the well cap  

In addition, you should test your well at a minimum for coliform bacteria each year, usually in the spring (or the wet season), and if there is any change in the taste, color or odor of your drinking water. A confirmed positive test for coliform bacteria requires disinfection at the least. I will not chlorinate my well until after I review the results of my recent well testing. The approach I would take to disinfect the well and plumbing systems is a little more involved (and inconvenient) than what I would do for iron bacteria alone.