Coliform and E.Coli Bacteria Water Contamination?

Coliform and/or E.Coli Bacteria In Your Well Water?

Bacteria exist in many well waters, especially shallow or poorly constructed wells under the influence of water from the surface.  However even if your well is a deep properly constructed well, it can become accidentally contaminated by coliform bacteria. Septic tanks can contaminate drinking water wells with bacteria.  In some cases, wells are contaminated as a result of recent service or pump repair work.

Other sources of bacterial contamination may include run-off from yards, feedlots, pastures, canine runs, and other farm land areas where animal waste products are deposited. Insect pests, rodents and/or wildlife coming into the well can also be reasons for pollution. Harmful microorganisms can enter a water source thru infiltration by means of floods or possibly by surface run-off during heavy periods of rainfall.

Contamination from pathogenic bacteria can cause serious health problems in many private water systems. Coliform (often referred to as “total coliform”) may not cause disease, but can be indicators of disease-causing bacteria such as E.coli or fecal coliform. The latter causes intestinal problems such as dysentery, hepatitis, cholera and typhoid fever.  E.Coli is a form of coliform that is found in the guts of warm blooded mammals such as people, pets, livestock and wild animals.

Intestinal tract infections and dysentery are often thought to be minor health problems. They can, however, prove deadly to newborns, the aging population, and those that are ill. In certain areas typhoid, hepatitis and cholera are passed on through contaminated water sources. A water analysis is required to determine whether bacteria exist in your water supply.

If bacteria is present in your well or spring water, an effort should be made to establish and remove the origin of the contamination. Human and animal waste products are a prime source of unhealthy bacteria in water.   the first and most important step is attempting to identify the source of the contamination and try to stop the contamination in the first place.
When to Analyze for Coliform Bacteria

If your water comes from your own private source, you are in charge of getting it tested to make sure it is safe.water source subjected to testing to confirm its safety.

When to have your well water tested for coliform bacteria:

  • At least one time each year;
  • If your well is new, or after it has been repaired or serviced
  • At any time if your well has been affected by flood waters or surface run-off;
  • At any time when microbial pollution is actually suspected, as could be indicated by ongoing disease
Like, Share, and Join Our Community
Gerry Bulfin

Gerry Bulfin is the founder and owner of Clean Water Systems & Stores, Inc. (Clean Water Store) in Santa Cruz, California, which he started in 1986. He is a WQA Master Water Specialist, WQA Certified Installer, California Grade II Water Treatment Operator, and California Licensed Contractor (C-55 Water Conditioning), CSLB #1003944. Gerry is a long-time member of the Water Quality Association (WQA), the National Ground Water Association (NGWA) and the American Water Works Association (AWWA), and shares practical, test-based advice on choosing, installing and maintaining well and city water treatment systems.

Recent Posts

Why Does My City Tap Water Smell Musty or Earthy Right Now?

If your tap water has started smelling or tasting a little "off" this week: earthy,…

3 months ago

Why Does My Well Pressure Drop in Summer? (And What it Costs to Fix)

If your water pressure has been weaker than usual this month, you're not imagining it.…

3 months ago

Is Your City Testing for This?

Is Your City Testing for This? Every year, your water utility sends out a report.…

3 months ago

Acid Neutralizer vs. Soda Ash for Well Water: Which One Do You Need?

Article last updated July 2026 If your well water is acidic, with a pH below…

3 months ago

What Water Treatment System Do I Actually Need? A Buyer’s Guide by Symptom

Most homeowners come to us knowing something is wrong with their water. The smell, the…

3 months ago

Carbon Backwash Filter for City Water: What It Does, What It Doesn’t, and How to Size It

If you are on city water and dealing with chlorine taste and odor, chemical smell…

3 months ago