Answer Hub
Tank & Bore Water Testing FAQs
Clear answers about rainwater tank testing, bore water testing, bacteria, minerals, sample collection and what your results mean.
This page answers the questions most Sunshine Coast households on tank or bore water actually ask us. Results are interpreted against the Australian Drinking Water Guidelines (ADWG) — we report what the numbers say and what the typical next step looks like, so you can decide on inspection, filtration, UV or specialist follow-up alongside your installer or Pristine Water Systems.
Tank water testing
Rainwater tank questions — testing cadence, what changes after rain or cleaning, and what to do if a result is flagged.
Is rainwater tank water suitable to drink?
Rainwater tank water can be a useful supply when the tank, roof catchment and gutters are well maintained, but quality varies between properties and seasons. Testing helps identify what needs attention — for example bacterial contamination after debris ingress, or low pH affecting plumbing. SCWT does not assess medical suitability; we report against the Australian Drinking Water Guidelines (ADWG) so you can decide on filtration, UV, cleaning or further investigation alongside your installer or Pristine Water Systems.
How often should I test my rainwater tank water?
Most households on tank water benefit from a yearly check, plus a re-test after any major event — first-flush failure, debris in the tank, suspected contamination, or after tank cleaning or filter changes. Properties with babies, immunocompromised residents, or food preparation needs often test more frequently. The Essential Tank Water Test is the right starting point for annual screening.
What does a tank water test check for?
The Essential Tank Water Test covers the bacterial and chemical markers most relevant to rainwater catchments: E. coli, total coliforms, pH, total dissolved solids (TDS), conductivity, turbidity, and other parameters that reflect catchment hygiene and tank condition. If you only need a quick microbiology screen, the Basic Water Safety Check is the lighter option. Specialist contaminants (pesticides, PFAS, glyphosate) are not in the standard packages — see the specialist-testing question below.
Should I test my tank water after heavy rain?
Heavy rain can flush accumulated dust, bird droppings, leaves and roof debris into the tank, especially if the first-flush diverter is overdue or undersized. A microbiology test in the days after a major event is a sensible check — results will tell you whether your catchment hygiene held up or whether maintenance is overdue. Don't sample DURING the storm; wait until flow has settled.
Should I test after tank cleaning or filter changes?
Yes — a post-service test confirms the work has done what was expected and gives you a clean baseline for future comparisons. We recommend allowing 24–48 hours after refilling so the water has time to settle and any residual disturbance has cleared.
Why does my tank water smell, taste earthy, or look cloudy?
Earthy or musty taste often points to organic matter or biofilm in the tank; cloudiness can be suspended sediment or microbial bloom; a chlorine-like smell can come from rooftop debris reactions. None of these alone diagnose a problem — testing identifies whether what you're noticing is a microbiology issue, a chemistry issue, or simply a tank that needs cleaning. Bring a sample and we'll report against ADWG so the next step is clear.
Can roof debris, leaves, birds, possums or frogs affect tank water?
Yes — any organic load on the roof or in the tank can affect microbial counts. Properly maintained gutters, gutter mesh, a working first-flush diverter, and an inlet strainer reduce this risk significantly. If wildlife access to the tank inlet is suspected, that's a strong reason to test microbiology and inspect tank seals.
Does a water filter mean I don't need to test my tank water?
No — filters target specific issues (sediment, taste, some bacteria) and need to be sized and maintained correctly to perform. Testing is what tells you whether the filter is doing what you bought it for, and whether the upstream supply has changed. We recommend testing both before installing filtration (to size the system correctly) and periodically afterwards.
Does UV sterilisation mean I don't need to test my water?
UV systems are effective against many micro-organisms when correctly sized, sleeved, powered and maintained — but only if the water entering the UV chamber is clear (high turbidity blocks UV). Testing confirms the system is performing and the upstream water is in spec. A UV system silently failing without a backup test schedule is a common preventable issue.
What should I do if my tank water test is flagged?
Don't panic — a flagged result means the sample doesn't meet one or more Australian Drinking Water Guidelines values and warrants attention. Start by reviewing recent weather, tank maintenance history, first-flush condition, gutters and any visible debris. Pristine Water Systems can help with practical next steps — tank cleaning, filtration sizing, or UV — if treatment or remediation is required. A re-test confirms whether the action resolved the issue.
Bore water testing
Bore water questions — what to test, what staining and smells mean, and how bore chemistry can shift over time.
Is bore water suitable to drink?
Bore quality varies enormously between properties and even between seasons on the same bore. Many Sunshine Coast bores carry mineral loads (iron, manganese), salinity or microbial contamination that need attention before the water is used for drinking, cooking or food prep. Testing helps identify what needs attention so you can match treatment to the actual chemistry rather than guessing. SCWT reports against ADWG; we don't make medical claims.
What should bore water be tested for?
The Essential Bore Water Test covers the chemistry that matters most on local bores — E. coli, total coliforms, pH, TDS, conductivity, iron, manganese, hardness and other markers. This is the right starting test for almost every Sunshine Coast bore. If the bore has known specialist risks (e.g. historic agricultural use), the result is best interpreted alongside site history and the bore log.
Why does bore water stain toilets, sinks, driveways or fences?
Rust-coloured or orange stains usually indicate iron; black or purple-brown stains point to manganese; white scale typically reflects hardness or high TDS. These are common on local bores and the right filtration depends on which metal is dominant and at what level. Testing tells you the numbers so you can size oxidation/filtration correctly rather than over- or under-treating.
What causes bore water to smell like rotten eggs?
A rotten-egg smell is typically hydrogen sulphide, produced by sulphate-reducing bacteria deep in the bore or aquifer. It's an aesthetic and corrosion issue more than a microbial drinking-water indicator, but it often coincides with elevated iron or manganese. Testing confirms whether other parameters need attention; aeration, oxidation or specific filtration usually resolves the smell.
What do iron and manganese mean in bore water?
Both are naturally-occurring minerals dissolved from surrounding rock. They cause staining, taste and scale issues at moderate levels and are flagged by ADWG above defined limits. They aren't acutely hazardous at typical bore concentrations, but they often signal a need for oxidation/filtration to protect plumbing, hot-water systems and laundry. The Essential Bore Water Test reports both.
What does high salinity or high TDS mean?
High TDS or conductivity reflects dissolved salts and minerals — common on coastal aquifers and some hinterland bores. Above the ADWG aesthetic limits the water tastes brackish, scales hot-water systems, and corrodes fittings; very high TDS can rule the bore out for drinking entirely. Treatment options depend on the level — testing tells you whether you're dealing with a mineral issue, a salinity issue, or both.
Can bore water contain bacteria?
Yes — bores can be contaminated by surface ingress (damaged headworks, cracked casing, nearby septics), by stagnation, or by biofilm in the bore itself. E. coli or total coliforms in a bore is a serious finding because the source is below ground and bacterial presence usually indicates a pathway from the surface. A flagged bore microbiology result warrants inspection of the bore headworks and surrounds before any treatment is sized.
How often should bore water be tested?
Annually as a baseline, plus after any change you can observe — colour, smell, taste, staining, neighbouring construction, drought conditions, or pump replacement. Bore chemistry can shift slowly with the surrounding aquifer, so a yearly snapshot keeps you ahead of issues.
Should I test bore water before installing filtration?
Yes — sizing filtration without test results is guesswork. The right oxidation media, filter type, and capacity depend on the iron/manganese/hardness/pH numbers. A pre-installation test and a post-installation confirmation test together prove the system is doing what it was specified to do.
Can bore water quality change over time?
Yes. Aquifer levels shift with rainfall, neighbouring use and drought; surface ingress risks rise with corrosion of headworks; biofilms develop in stagnant zones. A yearly test catches drift before it becomes a noticeable problem, and re-testing after any observed change (colour, taste, staining) confirms whether action is needed.
Bacteria, E. coli & coliforms
What microbiology results actually mean — and why they're time-sensitive.
What is E. coli in water?
E. coli is a bacterial group used as an indicator of recent faecal contamination — from animal or human sources. Its presence in a drinking water sample is treated as a significant finding under ADWG. Detection doesn't diagnose a health problem; it indicates the supply does not meet drinking-water criteria and the source pathway should be investigated.
What are total coliforms?
Total coliforms are a broader bacterial family that includes E. coli plus other environmental bacteria. They're used as a general indicator of catchment hygiene and tank/bore integrity. Presence of total coliforms without E. coli is common in tank supplies and usually points to general catchment or tank-cleanliness issues rather than recent faecal ingress.
What does it mean if E. coli is detected?
E. coli detection means the sample does not meet Australian Drinking Water Guidelines and should be addressed. The next step is to look at the tank, roof catchment, gutters, first-flush, filtration, UV system, recent weather and maintenance history. SCWT provides the test result; Pristine Water Systems can help with practical next steps if cleaning, treatment or filtration is required, followed by a confirmation re-test.
What does it mean if total coliforms are detected but E. coli is not?
This pattern is common in rainwater tanks and usually points to environmental bacteria — biofilm in the tank, dust ingress, or organic matter in the catchment — rather than faecal contamination. It still does not meet ADWG and warrants attention: typically tank inspection, cleaning, first-flush review, and a follow-up test to confirm improvement.
Why are microbiology samples time-sensitive?
Bacterial populations in a sample bottle change continuously after collection — both growth and die-off shift the result away from what was actually in your supply at the moment of sampling. ADWG-aligned labs aim to start microbiology analysis within 24 hours, kept cool in transit. That's why we recommend drop-off the same day where possible and a cooler bag in the car if it's a hot drive.
Colour, smell, taste & staining
What you can — and can't — tell from how water looks, smells or tastes.
Why does my tank or bore water look cloudy?
Cloudiness (turbidity) usually points to suspended particles — sediment, algae, biofilm fragments or iron precipitates. It can also block UV systems, which is why turbidity is a standard part of the Essential tests. Testing measures it as a numeric value (NTU) against the ADWG aesthetic limit, so the next step (settling time, filtration, tank inspection) can be matched to the level.
Why does my water smell or taste different?
Aesthetic changes — earthiness, mustiness, metallic taste, chlorine-like smell — usually have a chemistry or microbiology explanation. They're not diagnostic on their own, but they're useful prompts to test. Most aesthetic complaints resolve once the underlying issue is identified and addressed.
Why is staining appearing on my fixtures, driveway or fence?
Orange/rust → iron; black/purple-brown → manganese; white scale → hardness; green-blue → low-pH copper attack on plumbing. Testing tells you which it is and at what level so the right filtration or pH-correction approach can be sized rather than guessed at.
Does colour and taste tell me whether my water meets ADWG?
No — colour, smell and taste catch some issues but miss many of the ones ADWG actually targets. Most microbiology results, low-level metals and pH drift produce no visible signal at all. That's why an annual test is recommended even when the water looks fine.
Sample collection & turnaround
How to collect, store and drop off a sample so the result reflects your actual supply.
Can I collect the water sample myself?
Yes — most SCWT customers collect their own samples. For microbiology we provide a sterile bottle and a quick guide: collect from a representative tap, don't touch the rim, fill to the line, cap immediately. For chemistry you can use a clean bottle of the right volume. Same-day drop-off keeps the result meaningful, especially for microbiology.
How much water do I need to collect?
About 250 mL for a microbiology sample, and 500–1000 mL for a chemistry panel — see the sample-collection guide that comes with your booking. Over-filling isn't a problem, but under-filling a microbiology bottle can compromise the test.
How quickly should I drop off the sample?
Same day where possible — ideally before 2pm Monday to Thursday at our Noosaville lab at Unit 1/37 Gateway Drive. Microbiology starts to drift after 24 hours even when kept cool; chemistry is more forgiving but same-day still gives the cleanest result.
Why should the sample be kept cool?
Bacterial populations in the sample bottle keep changing after collection — warmth accelerates that drift. Keeping the sample in a fridge or cooler bag between collection and drop-off preserves the snapshot of your actual supply. A simple ice brick in an insulated bag is fine for short trips.
Can I bring a sample in any bottle?
For microbiology, no — use the sterile bottle we provide so trace bacteria from a previous bottle's contents don't skew the result. For chemistry a clean bottle is usually acceptable if it hasn't held anything else, though we still recommend our supplied bottles for the most reliable result.
Understanding results & next steps
How to read the report, what 'doesn't meet ADWG' means, and how the membership Passport fits in.
What happens after I receive my report?
Your report includes each parameter, the ADWG benchmark, and a plain-English summary of which (if any) values warrant attention. If everything is within ADWG, no further action is needed beyond your usual maintenance cadence. If anything is flagged, the report explains what type of issue it suggests and the typical next-step categories — inspection, cleaning, filtration, UV, or further specialist testing.
What does 'does not meet Australian Drinking Water Guidelines' mean?
ADWG sets the reference values used across Australia for drinking-water quality. A parameter that doesn't meet ADWG should be addressed — the right action depends on which parameter, by how much, and the rest of the site context. Results should be interpreted alongside site conditions, water source, treatment system and intended use; the report is a starting point for that conversation.
Can Pristine Water Systems help after testing?
Yes — PWS specialises in tank cleaning, filtration design and treatment systems for tank and bore supplies. When a result is flagged or you want to size filtration correctly, PWS can quote and install based on your actual numbers rather than a generic recommendation. SCWT and PWS work alongside each other but stay independent on the testing side.
What is a Water Health Passport?
The Passport is an optional ongoing record that tracks your water test results over time on a single property timeline — annual screens, post-event re-tests, post-treatment confirmations. It makes longer-term changes (slow mineral creep, recurring rain-related shifts) much easier to see than reading individual one-off reports.
SCWT test packages
Which package to choose — and what's not in the standard offering.
What is included in the Basic Water Safety Check?
The Basic Water Safety Check ($99 / $79 online prepaid) is a microbiology-focused screen — E. coli and total coliforms — useful when you want a quick bacterial check after a specific event (rain, cleaning, suspected ingress) without a full chemistry panel.
What is included in the Essential Tank Water Test?
The Essential Tank Water Test ($179 / $143 online prepaid) is the standard annual check for rainwater tanks — microbiology (E. coli, total coliforms) plus chemistry markers (pH, TDS, conductivity, turbidity and related parameters) tuned to the issues catchments commonly raise.
What is included in the Essential Bore Water Test?
The Essential Bore Water Test ($199 / $159 online prepaid) extends the standard chemistry panel to cover the metals and mineral parameters most relevant to local bores — iron, manganese, hardness, salinity-related markers — alongside microbiology.
Which test should I choose?
If you want a quick bacterial check after an event, start with the Basic Water Safety Check. If it's your annual rainwater tank screen, the Essential Tank Water Test is the right baseline. If it's bore water — almost always the Essential Bore Water Test, because metal/mineral data matters as much as microbiology. If you're unsure, the booking flow recommends one based on your supply type.
Can SCWT test for pesticides, herbicides, PFAS, glyphosate or other specialist contaminants?
These are not in the standard SCWT packages. Specialist contaminant analysis is typically routed through accredited NATA laboratories with extended scope, and we can refer you to suitable labs or work alongside them when the standard panel suggests a specialist follow-up is warranted. We'd rather refer accurately than mis-scope a test.
Town water & other questions
Quick answers about scope and a few common edge cases.
Do you test town water?
SCWT focuses on tank and bore water — the supplies where local households actually need independent visibility. Town water is monitored by your supply utility under regulatory testing schedules. If you have a specific concern about town water (plumbing-side staining, taste changes after works), we can discuss whether targeted in-house testing is useful, but it's not a standard offering.
Still have a question?
If your question isn't here, the team can help. Book a test online, browse the Knowledge Hub for longer-form articles, or see whether your suburb already has a dedicated page.