Coliform and E. coli
What do I do about bacteria in my well water?
Shallow and surface-influenced wells can take in bacteria after heavy rain, snowmelt or flooding. There is no taste or smell warning.
How you notice it
- A positive coliform or E. coli lab result
- Cloudiness after heavy rain or snowmelt
- Pit or bored well, or casing below grade
- Unexplained stomach upset in the household
Why it happens
Sand-and-gravel and shallow bedrock aquifers connect to surface water. Poor casing seals and flooded well pits are the other common route in.
The fix
- Shock-chlorinate, then retest twice two weeks apart
- UV disinfection last in the treatment train, downstream of all filtration
- 5-micron prefilter so UV gets clear water
- Fix the wellhead: extend casing above grade and seal the cap
Equipment that solves it
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iSpring UVF55FS 12 GPM Whole-House UV Disinfection System
Inactivates coliform and E. coli without chemicals. Features smart flow sensor switch. Mandatory on surface-influenced wells.
Check price on AmazonRefills & maintenance
iSpring UVB55FS 55W UV Replacement Lamp (for UVF55FS)
5 Micron 10″×2.5″ Sediment Filter 6-Pack (PP Spun)
Aquaboon 10″×4.5″ CTO Carbon Block Cartridge (2-Pack)
AquaVial E. coli & Coliform Well Water Screening Kit (2-Pack, Made in Canada)
Watersafe Bacteria Test (Silver Lake Research)
SpringWell Black Comb Monitored Whole-House UV System
Continuous optical sensor monitoring with digital countdown controller. Tracks germicidal UV intensity for private well disinfection.
$150 USD/yr consumables · premium
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iSpring UVB55FS 55W UV Replacement Lamp (for UVF55FS)
Replacement 55W UV lamp for the iSpring UVF55FS whole-house system. Change about yearly (≈9,000 hours) so dose stays effective against coliform on private wells.
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UV Lamp + Quartz Sleeve + O-Rings Kit (VIQUA / Trojan Compatible)
Annual replacement UV lamp, quartz sleeve, and o-rings for standard Canadian VIQUA / Trojan-style reactors. Maintains verified germicidal UV-C dose.
Check price on AmazonWatersafe Bacteria Test (Silver Lake Research)
Bacteria test from Silver Lake Research, an alternative to the AquaVial E. coli & coliform kit. Confirm a positive with an accredited laboratory.
Check price on AmazonWorks with: AquaVial E. coli & Coliform Well Water Screening Kit (2-Pack, Made in Canada)
Frequently asked questions
What do I do about bacteria in my well water?
Shallow and surface-influenced wells can take in bacteria after heavy rain, snowmelt or flooding. There is no taste or smell warning. Sand-and-gravel and shallow bedrock aquifers connect to surface water. Poor casing seals and flooded well pits are the other common route in.
How do I know if I have coliform and e. coli?
Common signs include: A positive coliform or E. coli lab result; Cloudiness after heavy rain or snowmelt; Pit or bored well, or casing below grade. Confirm with an accredited lab before buying treatment gear.
What is the fix for coliform and e. coli?
Shock-chlorinate, then retest twice two weeks apart UV disinfection last in the treatment train, downstream of all filtration 5-micron prefilter so UV gets clear water Fix the wellhead: extend casing above grade and seal the cap
Should I treat the whole house or just drinking water?
Staining, scale, and bacteria risks are usually whole-home issues. Taste, dissolved solids, and some metals can be finished at a kitchen RO tap after the main train is correct.
How do I match this problem to my municipality?
Open the provincial directory and the municipality page if one is published. This guide does not list places from a hardness or depth model.
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