Filtration Guide
Well water treatment, in the order it installs
Treatment is a train, not a single box. Each stage protects the one after it, so order matters more than brand. Below is what every stage does. Which ones you need comes from a laboratory test, not from a number on this site.
Build my systemThe seven stages
- 1
Test first
An accredited lab panel is the only thing that sizes equipment. Everything downstream is guesswork without hardness, iron, manganese and bacteria numbers.
- 2
Sediment prefilter
Catches sand and turbidity so it never reaches softener resin, UV quartz sleeves or pump seals.
- 3
Iron, manganese and sulfur
Air-injection oxidation converts dissolved metals to solids and filters them out. Always ahead of the softener.
- 4
Softening
Ion exchange trades calcium and magnesium for sodium. Sized in grains per day, not tank size.
- 5
Health-based reduction
Arsenic, uranium or nitrate reduction where the bedrock or land use calls for it.
- 6
Disinfection
UV last in the train, on clear water, at full service flow. Mandatory on surface-influenced wells.
- 7
Drinking water polish
Under-sink reverse osmosis for taste, dissolved solids and a final barrier at the kitchen tap.
Start from the problem
Each guide names the cause, the fix, the equipment, and the Canadian regions where that problem is common.
Recommendations are generated from Canadian regional well records. Links are affiliate links — we may earn a commission at no extra cost to you.
As an Amazon Associate I earn from qualifying purchases.
Whole-Home Softening
How do I soften hard well water?
Calcium and magnesium dissolved out of carbonate rock leave scale in kettles, heaters and fixtures, and stop soap from lathering.
Iron, Manganese & Sulfur
How do I remove iron from well water?
Dissolved iron oxidizes when it meets air, leaving orange staining; manganese leaves black specks and grey laundry.
Typical fix: iSpring WGB32BM 3-Stage Whole House Filter (20″ Big Blue)
Check price on Amazon Read the fixIron, Manganese & Sulfur
Why does my well water smell like rotten eggs?
Hydrogen sulfide gas, usually worse on the hot side, comes from sulfate-reducing bacteria or sulfur in the formation.
Typical fix: iSpring WGB32BM 3-Stage Whole House Filter (20″ Big Blue)
Check price on Amazon Read the fixUV Disinfection
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.
Typical fix: iSpring UVF55FS 12 GPM Whole-House UV Disinfection System
Check price on Amazon Read the fixArsenic & Uranium Reduction
Is there arsenic in my well water?
Fractured crystalline and shield bedrock releases arsenic and uranium naturally. Both are colourless, tasteless and health-based, not cosmetic.
Typical fix from $4,134 USD
Read the fixSediment Prefilter
Why is there sand in my well water?
Fine sand and turbidity from unconsolidated aquifers destroys softener resin, blocks UV and wears out pump seals.
Typical fix: iSpring WSP-50 Reusable Spin-Down Sediment Filter (50 Micron)
Check price on Amazon Read the fixRadon Aeration
Can radon get into well water?
Radon dissolved in groundwater is released into indoor air every time you shower or run a tap. Shield bedrock wells are the risk case.
Typical fix from $4,755 USD
Read the fixTest kits and DIY Big Blue parts
Hardness and bacteria test kits for a first check, and 20″ Big Blue housing and cartridge options for sediment, iron and sulfur. A laboratory test still decides what you need.
Recommendations are generated from Canadian regional well records. Links are affiliate links — we may earn a commission at no extra cost to you.
As an Amazon Associate I earn from qualifying purchases.
Varify Water Hardness Test Strips
An entry-level strip test: a quick, low-cost way to check water hardness before sizing a softener. A strip is a screening step, not a laboratory result.
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)
Pentair Pentek 150468 Big Blue 20″ Filter Housing (3/4″ Ports)
Whole-house DIY Big Blue housing for sediment and iron filtration, with 3/4″ ports. Fits standard 20″ × 4.5″ cartridges.
Check price on AmazonWorks with: 4.5″ × 20″ Refillable KDF 85 + KDF 55 + Carbon Cartridge, iSpring WGB32BM 3-Stage Whole House Filter (20″ Big Blue)
Refills & maintenance
4.5″ × 20″ Refillable KDF 85 + KDF 55 + Carbon Cartridge
4.5″ × 20″ Refillable KDF 85 + KDF 55 + Carbon Cartridge
Refillable KDF 85, KDF 55, and carbon cartridge for sulfur smell and iron, made for 20″ Big Blue housings.
Check price on AmazonWorks with: Pentair Pentek 150468 Big Blue 20″ Filter Housing (3/4″ Ports), iSpring WGB32BM 3-Stage Whole House Filter (20″ Big Blue)
Next steps
Pair this guide with a municipal page or the products catalog. Size equipment from a laboratory test.
Frequently asked questions
In what order should well water treatment be installed?
Treat water as a train: test first, then sediment prefilter, iron/manganese/sulfur oxidation, softening, any health-based reduction (arsenic/uranium/nitrate), UV disinfection on clear water, and optional under-sink RO for drinking water. Each stage protects the next.
Do I always need a water softener?
Only when a laboratory test shows hardness high enough to cause scale and soap problems. The USGS (2018) bands reprinted by Health Canada call 121–180 mg/L hard and anything above 180 mg/L very hard, as CaCO₃. Softeners are sized in grains per day from that lab result.
Why test before buying equipment?
An accredited lab panel for hardness, iron, manganese, bacteria, and metals is the measurement that sizes resin, oxidizers, and UV. A municipal page shows a hardness range only when a published study covers that place and aquifer. Do not size equipment from it.
What is the difference between an iron filter and a softener?
An air-injection iron filter oxidizes dissolved iron, manganese, and often hydrogen sulfide ahead of other gear. A softener uses ion exchange for calcium and magnesium scale. Iron should be removed before softener resin so the bed does not foul.
How do regional reports connect to filtration?
Municipal pages repeat what the public well registry recorded for that place. A hardness range is shown only when a published study covers that place and aquifer. No drilling price is shown. Use this filtration guide for the treatment order, and a laboratory test to decide which stages you need.
Does this site estimate what treatment will cost?
No. The products catalog shows merchant list prices for non-Amazon merchants, and Amazon.ca items link to Amazon for the current price. It does not add them into an installed cost, and it does not price drilling. The symptom checklist only points at catalog items that match what you report.
This guide describes treatment stages. It does not estimate hardness, depth, or cost for a municipality. Size equipment on your own lab result.