Well Water Testing Reference
Overview
Well water requires more testing than municipal because there's no central treatment + the water composition varies significantly. Annual testing is recommended; pre-purchase testing essential.
When to test
- At property purchase: always test before buying a home with well water
- Annually: best practice
- After flooding or contamination event: immediately
- After well work: any drilling, cleaning, or pump replacement
- When water taste/smell/appearance changes: investigate immediately
- When family member is ill: rule out water cause
Standard well water test parameters
Mandatory:
Bacteria (E. coli + total coliform):
- Presence indicates contamination from septic, animal waste, or surface intrusion
- Threshold: ZERO acceptable
-
- coli specifically indicates fecal contamination
Nitrates:
- From agricultural runoff, septic
- Health hazard, especially for infants (methemoglobinemia / "blue baby")
- Threshold: < 10 mg/L
Lead:
- From old plumbing or solder
- Health hazard at any level
- Particularly concerning for children + pregnant women
Arsenic:
- Naturally occurring in some geology
- Cancer risk over long-term exposure
- Threshold: < 10 ppb
pH:
- Indicates corrosivity
- Affects plumbing + treatment effectiveness
Hardness:
- Indicates calcium + magnesium
- Affects soap, scale, water heaters
Iron + manganese:
- Indicates staining + taste issues
- Levels > 0.3 ppm iron typically require treatment
Recommended add-ons:
TDS: total dissolved solids Conductivity: indicator of dissolved ions Sulfate: can cause GI issues at high levels Chloride: indicator of salt water intrusion or septic contamination Sulfide (rotten egg): olfactory + health concern Radon: in radon-prone areas Fluoride: important for children Mercury, chromium, copper, zinc: trace metals Sodium: especially for low-sodium diets
Premium / specific area:
Pesticides: agricultural areas Herbicides: agricultural areas Volatile organic compounds (VOCs): industrial pollution areas Petroleum hydrocarbons: near gas stations, pipelines
Test methods
On-site reagent tests:
- Hardness, pH, chlorine, total iron
- Quick + cheap ( for kit)
- Less accurate
Lab testing:
- Most accurate
- Comprehensive
- depending on parameters
Send samples:
- Use lab-supplied sample containers
- Follow lab instructions for sample collection
- Refrigerate if specified
- Ship overnight (especially bacteria samples)
Sample collection (lab)
For accurate results:
- Choose representative tap (kitchen typically)
- Run water 2-3 minutes to clear stagnant water (flush both hot + cold)
- Bottle for bacteria: STERILE container, no chlorine on it
- Don't touch the inside of bottle
- Fill to specified level
- Label per lab requirements
- Refrigerate if not shipping immediately
- Ship overnight for bacteria tests
Standard testing labs
- State health department lab (often free for basic tests)
- Private labs: many specialty options
- Cost: depending on parameters
Interpreting results
For each parameter, lab reports:
- Test result
- EPA limit OR state limit
- "Action level" (sometimes lower)
- Recommendation
For "exceeds limit" parameters:
- Consult with customer
- Recommend appropriate treatment
- Sometimes recommend lab re-test to verify
Common well water problems by region
Northeast: arsenic (granite geology), iron, radon
Southeast: iron, sulfur, low pH (acidic), nitrates
Midwest: nitrates (agricultural), hardness, iron
Southwest: hardness, arsenic, TDS, sometimes fluoride
West coast (mountain): soft water, sometimes radon, mineral deposits
Test result + treatment matching
| Test result | Recommended treatment |
|---|---|
| Coliform/E. coli positive | UV + shock chlorination |
| Nitrates > 10 mg/L | RO at kitchen tap + investigation |
| Lead | RO or specialty filter |
| Arsenic | RO or specialty filter |
| Iron > 0.3 ppm | Iron filter |
| Hardness > 7 GPG | Softener |
| Low pH | Calcite neutralizer |
| Sulfide | Aeration + carbon |
Customer education
Help them understand:
- Their well is their water utility
- Annual testing is responsibility
- Testing costs typically
- Contamination can develop suddenly
- Some contaminants tasteless + invisible
- Treatment is investment in family health
When testing finds issues
Approach the customer with:
- Specific findings: "Iron at 1.2 ppm; standard is < 0.3 ppm"
- Health implications: cancer risk, infant risk, etc.
- Treatment options: with cost
- Re-test schedule: every 6 months OR annually after treatment
- Document everything: customer needs records
Free water testing programs
Some states/localities offer:
- Free well-water testing kits
- Reduced-cost lab services for low-income
- Free testing after disasters
Always inform customers about these programs.
Long-term water quality management
Best practices for well owners:
- Annual basic test
- Comprehensive test every 3-5 years
- Records retained (helps identify trends)
- Well inspection (visual + flow rate) annually
- Septic inspection (well + septic interaction)
NEVER assume well water is safe based on taste, smell, or appearance. Many serious contaminants (lead, arsenic, nitrates, bacteria) have no taste, smell, or visible indication. The only way to know is testing. As a water treatment professional, you have an ethical obligation to recommend annual testing - even if customer "doesn't want to spend the money." Health is at stake.
References
- EPA Safe Drinking Water Act standards
- CDC well water testing guidance
- State health departments
- Manuall internal: Water Chemistry Basics, Water Filtration Technologies Reference