Tap Water Quality in Gretna, TAS
Postcode 7140 · Supplied by TasWater via New Norfolk Greater Hobart
Quality Score
About Gretna
Gretna is a suburb of 254 residents in Tasmania (postcode 7140). The median age is 38. It falls within the TasWater area. Neighbouring suburbs include Black Hills, Boyer, Bradys Lake, Butlers Gorge.
Most residents own their home with a mortgage (46%), while 40% own outright, while 17% rent. The median household income is $72,176 per year. The top countries of birth for residents are United Kingdom (71%), India (24%), and Ireland (24%).
Tap water in Gretna is supplied by TasWater. The suburb receives water via the New Norfolk Greater Hobart supply zone.
Water quality summary
Based on recent water quality reports, Gretna achieves a WaterScore of 9.7 out of 10, rated excellent overall. Water hardness measures 41.055556 mg/L, classified as soft. This is gentle on appliances and skin, with minimal limescale buildup expected. The pH level is 7.299961, which is within the ADWG guideline range of 6.5–8.5. Chlorine, used for disinfection, measures 0.873906 mg/L — well within the ADWG guideline of 5 mg/L. Some residents may notice a slight taste, which can be reduced by refrigerating water or using a carbon filter. Total dissolved solids (TDS) measure 78.666667 mg/L, considered low against the ADWG guideline of 600 mg/L. Turbidity is 0.292812 NTU, indicating clear water, within the ADWG guideline of 5 NTU. E. coli was not detected in testing, meeting the ADWG standard for microbiological safety.
Compare with nearby suburbs: Black Hills , Boyer , Bradys Lake
Census Data
Suburb snapshot
Population
Median Age
Median Income
Owner-occupied
Recommended filters for Gretna
Products matched to your water profile
BRITA
Marella 2.4L Fridge Water Filter Jug (Maxtra+)
4.7 · 16,095 ratings on Amazon
Ideal for Gretna — removes chlorine taste and odour.
Waterdrop
TSA Under-Sink Filter (Fluoride + PFAS)
4.4 · 2,237 ratings on Amazon
A reliable tsa under-sink filter (fluoride + pfas) suitable for Gretna's water profile.
Purewell
8.5L Stainless Steel Gravity System
4.4 · 1,137 ratings on Amazon
Ideal for Gretna — removes chlorine taste and odour.
Comparison
How Gretna compares
Compared to Tasmania and national averages
| Metric | Gretna | TAS Avg | National Avg |
|---|---|---|---|
| Hardness | 41.055556 mg/L | 34.8 mg/L | 85.1 mg/L |
| pH | 7.299961 | 7.4 | 8.4 |
| Fluoride | — | 0.9 mg/L | 0.7 mg/L |
| Chlorine | 0.873906 mg/L | — | — |
| Turbidity | 0.292812 NTU | 0.3 NTU | 0.4 NTU |
| TDS | 78.666667 mg/L | 93.3 mg/L | 275.7 mg/L |
Full Results
Detailed water quality data
All values compared against Australian Drinking Water Guidelines (ADWG)
| Parameter | Value | Unit | ADWG Guideline | Status |
|---|---|---|---|---|
| Alkalinity | 17.888889 | mg/L | No limit | Measured |
| Aluminium | 0.043 | mg/L | < 0.2 | Good |
| Ammonia | 0.002056 | mg/L | No limit | Measured |
| Antimony | 0.001 | mg/L | No limit | Measured |
| Arsenic | 0.001 | mg/L | No limit | Measured |
| Cadmium | 0.0002 | mg/L | No limit | Measured |
| Calcium | 13.4 | mg/L | No limit | Measured |
| Chloride | 9.8 | mg/L | < 250 | Good |
| Free Chlorine | 0.873906 | mg/L | < 5 | Good |
| Total Chlorine | 0.997222 | mg/L | < 5 | Good |
| Chromium | 0.001 | mg/L | No limit | Measured |
| Colour | 2.222222 | Pt-Co | < 15 | Good |
| Conductivity | 125 | uS/cm | No limit | Measured |
| Copper | 0.00225 | mg/L | < 2 | Good |
| Cyanide | 0.005 | mg/L | No limit | Measured |
| E. coli | 0 | MPN/100ml | < 0 | Compliant |
| Hardness | 41.055556 | mg/L | < 200 | Good |
| Iron | 0.014 | mg/L | < 0.3 | Good |
| Lead | 0.001 | mg/L | < 0.01 | Good |
| Magnesium | 1.7 | mg/L | No limit | Measured |
| Manganese | 0.00105 | mg/L | < 0.1 | Good |
| Mercury | 0.0001 | mg/L | No limit | Measured |
| Nickel | 0.001 | mg/L | No limit | Measured |
| Nitrate | 0.046111 | mg/L | < 50 | Good |
| Nitrite | 0.002 | mg/L | No limit | Measured |
| pH | 7.299961 | pH units | 6.5 – 8.5 | Normal |
| Sodium | 4.35 | mg/L | < 180 | Good |
| Sulfate | 22.166667 | mg/L | < 500 | Good |
| Temperature | 12.878906 | degrees C | No limit | Measured |
| Total Coliforms | 0 | MPN/100ml | < 0 | Compliant |
| Total Dissolved Solids | 78.666667 | mg/L | < 600 | Good |
| Trihalomethanes | 0.0203 | mg/L | < 0.25 | Good |
| Turbidity | 0.292812 | NTU | < 5 | Good |
| Zinc | 0.00235 | mg/L | No limit | Measured |
Safety
Safety assessment
Based on 34 parameters tested, all results fall within Australian Drinking Water Guidelines. E. coli was not detected, meeting the ADWG standard for microbiological safety.
Based on comparison with Australian Drinking Water Guidelines (ADWG)
Explained
What these numbers mean
Soft (41.055556 mg/L)
Water Hardness
Your water is classified as soft, which means minimal limescale buildup on fixtures and appliances. Soap and shampoo will lather easily, and you should notice no drying effects on skin or hair. Hot water systems and kettles are unlikely to suffer scale-related efficiency losses.
Normal Range
pH Level
pH of 7.299961 is within the ideal range of 6.5–8.5. The ADWG recommends pH between 6.5 and 8.5 for drinking water.
Data unavailable
Fluoride
Fluoride data is not currently available for Gretna.
Chlorine
Disinfection
Chlorine measured at 0.873906 mg/L, well within the ADWG guideline of 5 mg/L. Used for disinfection to keep water safe. May affect taste slightly — refrigerating water or using a carbon filter can help.
Learn more about these measurements in our water quality glossary — including Hardness , pH , Fluoride , and ADWG guidelines .
Advice
Practical tips for residents
Chlorine Levels Are Low
Chlorine in Gretna measures 0.873906 mg/L, which is low. Filling a jug and letting it stand for 30 minutes will reduce any residual taste.
Soft Water Advantage
Gretna's water is soft at 41.055556 mg/L. You can use less soap and detergent, as it lathers easily with softer water.
Flush After Absence
If your home has been unoccupied for several days, run the kitchen tap for 30 seconds before drinking. This clears stale water that has been sitting in pipes.
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FAQ
Frequently asked questions
Is tap water safe to drink in Gretna?
How hard is the water in Gretna?
What water utility supplies Gretna?
Does Gretna water have fluoride?
What is the water quality score for Gretna?
What is the population of Gretna?
Supplier
Water utility
- Utility
- TasWater
- Supply Zone
- New Norfolk Greater Hobart
- Data Source
- TasWater — New Norfolk Greater Hobart
Nearby
Nearby suburbs
Same water utility, similar water quality
Similar Quality
Suburbs with similar water quality
Suburbs scoring between 8.7 and 10.0
Utility reports average the grid — not your home
Gretna's water meets ADWG standards at the source, but old pipes, roof tanks, and ageing plumbing can add lead, copper or bacteria before the water reaches your tap. These won't show up in your utility report.
Check your own tap before buying a filter or assuming the suburb average matches your home.
Tetra
EasyStrips 6-in-1 Water Test (100 strips)
4.6 · 8,650 ratings on Amazon
Tests 6 parameters in 60 seconds: hardness, chlorine, pH, nitrate, nitrite, alkalinity. Cheapest way to verify your utility data.
Test my tap →Sponsored Amazon link. Check Amazon for current price and availability.
Heavy Metals
Drinking Water Test Kit (Lead, Copper, Iron, Mercury)
4.2 · 250 ratings on Amazon
20 tests. Detects lead, copper, iron, mercury — the things utility reports miss. Mobile-app results, EPA-standard thresholds.
Check metals kit →Sponsored Amazon link. Check Amazon for current price and availability.
Guides for Hobart and Tasmania
In-depth articles on the water supply that serves Gretna
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Disclaimer: The information on this page is for general informational purposes only and does not constitute medical advice, health recommendations, or professional guidance. Water quality data is sourced from TasWater (annual report) and reflects conditions at the time of utility testing — it may not reflect real-time water quality at your tap. Actual water quality can vary due to local plumbing, seasonal changes, and distance from the treatment plant. For specific health concerns, consult a qualified health professional. For the most current water quality information, contact your local water utility directly. See our Terms of Use.