Bacteria in Drinking Water (E. coli & Coliform)
Harmful bacteria cause immediate illness including severe diarrhea, vomiting, and cramps. E. coli and coliform indicate fecal contamination from sewage or animal waste. Common in aging infrastructure and private wells.
Types of Harmful Bacteria
E. coli (Escherichia coli)
Most dangerous indicator. Presence means fecal contamination and potential for serious illness. Some strains (O157:H7) can be fatal, especially for children and elderly.
Fecal Coliform
Indicates recent fecal contamination from warm-blooded animals. Suggests presence of disease-causing organisms.
Total Coliform
Broader group of bacteria. May indicate water quality issues, though not necessarily dangerous. Triggers further testing for E. coli.
Other Dangerous Bacteria
- • Legionella (Legionnaires' disease)
- • Salmonella (food poisoning)
- • Shigella (dysentery)
- • Campylobacter (gastroenteritis)
Health Effects
Immediate Symptoms (1-3 days after exposure)
- • Severe diarrhea (often bloody)
- • Stomach cramps and pain
- • Nausea and vomiting
- • Fever and chills
- • Dehydration
- • In severe cases: kidney failure, death
Most Vulnerable: Infants, young children, elderly, pregnant women, and immunocompromised individuals face highest risk of serious complications.
EPA Standard
No E. coli or fecal coliform bacteria allowed in drinking water. Any detection requires immediate action and public notification.
How Bacteria Get Into Water
- •Sewage system breaks: Aging pipes, combined sewer overflows during heavy rain
- •Septic system failures: Common source for private wells
- •Animal waste runoff: From farms, feedlots, wildlife
- •Treatment system failures: Chlorination equipment malfunction
- •Flooding events: Surface water enters wells and distribution systems
Testing for Bacteria
When to Test
- • Private well: Test annually minimum
- • After flooding or heavy rain
- • If water appears, smells, or tastes unusual
- • Household members have unexplained GI illness
- • After any well maintenance or repair
- • Purchasing property with well
Testing Options
Cost: $20-75
- • County health department (often free or low-cost)
- • EPA-certified laboratory
- • Home test kits for screening (confirm positives with lab)
Results typically within 24-48 hours.
How to Kill Bacteria in Water
Immediate Action (If Contaminated)
1. Boiling (Emergency)
Boil water for 1 minute (3 minutes above 6,500 ft elevation). Kills all bacteria, viruses, parasites. Use for drinking, cooking, ice, brushing teeth.
2. Bottled Water
Use for all consumption until contamination resolved.
Long-Term Solutions
1. UV Disinfection Systems
99.99% effective - No chemicals, instant treatment. Point-of-entry systems treat all water. Cost: $300-900. Popular for private wells.
2. Chlorination
99.9% effective - Chemical disinfection. Whole-house systems available. Requires proper dosing and contact time.
3. Certified Filters
99.99% effective - Must be certified for bacteria removal (NSF Standard 53). Typically 0.2 micron or smaller. Reverse osmosis, ultrafiltration.
4. Well Shock Chlorination
One-time high-concentration chlorine treatment. Temporary fix - must address contamination source.
Important Notes
- • Standard carbon filters do NOT kill bacteria
- • Water softeners do NOT remove bacteria
- • Must identify and fix contamination source
- • Re-test after treatment to confirm effectiveness