What you can and can’t test at home
Home water testing options range from cheap indicator strips to sophisticated electronic meters. Understanding what each measures — and crucially, what it doesn’t — prevents expensive misunderstandings and misguided filter purchases.
| What you can test at home | Approximate cost | What it tells you |
|---|---|---|
| TDS (total dissolved solids) meter | $10–$30 | Total concentration of dissolved minerals — not what they are |
| pH test strips or meter | $5–$50 | How acidic or alkaline the water is |
| Chlorine test strips | $5–$20 | Free chlorine presence and approximate level |
| Chloramine test kit | $15–$40 | Chloramine level — requires specific kit, not standard chlorine strips |
| Iron test strips | $10–$30 | Approximate iron level |
| Hardness test strips | $10–$25 | Approximate total hardness (calcium + magnesium) |
| Nitrate test strips | $10–$30 | Approximate nitrate level — important for bore water |
| Bacteria/coliform test kit (post mail) | $40–$80 | Total coliforms and E. coli — sent to lab for analysis |
| What requires a laboratory | Why home tests can’t do this | Cost at accredited lab |
|---|---|---|
| PFAS (forever chemicals) | Requires LC-MS/MS instrumentation | $300–$600 per sample |
| Heavy metals (lead, arsenic, mercury) | Requires ICP-MS instrumentation | $150–$400 |
| Full microbiological panel | Requires culture media and incubation | $80–$200 |
| Specific disinfection byproducts | Requires GC-MS instrumentation | $200–$500 |
| Fluoride (precise level) | Ion-selective electrode or IC | Part of general chemistry panel ($100–$300) |
TDS meters — what they measure and the common misuse
A TDS (total dissolved solids) meter is the most widely sold home water testing tool in Australia. It measures the total concentration of dissolved ions in water by measuring electrical conductivity. It gives a reading in parts per million (ppm) or mg/L.
What TDS measures: the sum of all dissolved minerals, including calcium, magnesium, sodium, potassium, bicarbonate, sulphate, chloride, and many others.
What TDS does not tell you:
- Whether the dissolved minerals are harmful or beneficial
- Whether PFAS is present (PFAS does not significantly affect TDS)
- Whether chloramine or chlorine is present
- Whether bacteria are present
- Whether heavy metals like lead or arsenic are present
Testing chloramine vs free chlorine — a critical distinction
Standard chlorine test strips measure free chlorine. They do not accurately measure chloramine. If you are in a chloramine city (Sydney, Brisbane, Canberra, Perth south, outer eastern Melbourne) and you use a standard chlorine strip, you may get a low or zero reading — not because the water is unfiltered, but because the strip is testing for the wrong compound.
For chloramine testing, use a kit specifically labelled for total chlorine or chloramine. API Total Chlorine test kits and LaMotte DPD chloramine test tablets both measure total chlorine including chloramine. Available from pool supply stores and aquarium shops in Australia.
Testing before and after your filter
Testing tap water before and after a filter is the most useful home testing application. This tells you whether your filter is actually working and when cartridges need replacing.
For chlorine/chloramine: Test before and after the filter using total chlorine test tablets. A working catalytic carbon filter should reduce chloramine by 80%+ in the output. A result showing minimal reduction suggests the cartridge is exhausted or the media is not catalytic.
For TDS (RO systems): A TDS meter is useful specifically for RO systems. RO reduces TDS by 90–96%. If your TDS meter shows input water at 200 mg/L and RO output at 10 mg/L, the membrane is working. If RO output TDS creeps toward 50–100 mg/L, the membrane is degrading and replacement is due.
For bore water iron: Iron test strips before and after an iron reduction filter confirm whether the filter is removing iron effectively.
When to use a professional laboratory
Home tests are useful for monitoring known parameters. A professional laboratory is required when:
- You are testing bore water for drinking for the first time
- You have reason to suspect PFAS contamination (near airport, defence facility, or known affected area)
- You want to confirm lead levels, particularly in a pre-1980 building
- You want a comprehensive water quality baseline before purchasing any filter system
- A home bacteria test returns a positive indication
Accredited laboratories in Australia: ALS Water Testing, NATSWest (WA), Envirolab, Eurofins, and state government laboratories all provide accredited water analysis. Accreditation by NATA (National Association of Testing Authorities) is the standard to look for — NATA-accredited results are accepted by regulatory authorities. Costs range from $100 for a basic potability panel to $600+ for a comprehensive PFAS analysis.
Interpreting results against Australian guidelines
Australian Drinking Water Guidelines (ADWG) set limits across two categories: health limits (do not exceed) and aesthetic guidelines (palatability, taste, odour). Many parameters have aesthetic limits well below the health limit. Key reference points:
| Parameter | ADWG health limit | ADWG aesthetic guideline | Perth typical | Sydney typical |
|---|---|---|---|---|
| TDS | No health limit | 500 mg/L | 250–450 | 80–150 |
| Hardness | No health limit | 200 mg/L (scale) | 100–350 | 30–60 |
| Chlorine (free) | <5 mg/L | None | 0.2–0.5 | N/A (chloramine) |
| Chloramine | <3 mg/L | None | 0.5–1.5 (south) | 0.5–2.0 |
| Fluoride | 1.5 mg/L | None | 0.6–0.8 | 0.6–1.0 |
| Iron | None | 0.3 mg/L | 0.05–0.3 | <0.05 |
| Nitrate | 50 mg/L | None | Varies by bore | <5 |
| PFOA | 0.00056 mg/L (2025 ADWG) | None | Varies | Varies |
Your local utility publishes an annual water quality report with the actual measured values for your supply zone. Water Corporation (Perth), Sydney Water, Melbourne Water, Seqwater (Brisbane), and SA Water all publish these reports online and they are the most accurate reference for your specific suburb.
Frequently asked questions
- What does a TDS meter actually measure in tap water?
- A TDS meter measures the total concentration of dissolved ions in water using electrical conductivity. It tells you the combined level of all dissolved minerals — calcium, magnesium, sodium, bicarbonate, and others — but not which ones or whether they are harmful. A high TDS reading does not mean contamination. TDS meters do not detect PFAS, chloramine, bacteria, lead, or most contaminants people are actually concerned about.
- Can I test for PFAS at home?
- No reliable home PFAS test exists. PFAS compounds require laboratory analysis using liquid chromatography-mass spectrometry (LC-MS/MS) equipment. If you live near an airport, defence facility, or known PFAS-affected area, contact an NATA-accredited water testing laboratory for a PFAS panel. Costs range from $300-$600. Your state health department or local council may offer subsidised testing in documented affected areas.
- How do I know if my water filter is working?
- The test depends on what the filter is supposed to remove. For chlorine/chloramine: test the output with total chlorine test tablets — a working filter should show significant reduction. For RO systems: a TDS meter is useful — RO output should be 90-96% lower TDS than input. For iron filters: iron test strips before and after. For bore water bacteria filters: periodic laboratory testing of the filtered output.
- Where can I get my tap water professionally tested in Australia?
- NATA-accredited laboratories including ALS Water Testing, Envirolab, Eurofins, and NATSWest (WA) all provide residential water testing. Your state government health department may also provide testing or referrals. For PFAS specifically in known affected areas, some state governments offer subsidised testing — check with your local council or state health authority.