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australia:water_quality

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Table of Contents

drinking water quality meters

see also:

Introduction

  • these are designed primarily for “clean” water which looks like it could be drinkable (potable)
  • they are generally not for testing obviously dirty water
  • I am not sure they could be trusted to ensure you will not get gastro from the water if you drink it - better to sterilise it as per treating water to make it potable / drinkable HOWEVER sterilisation alone will not ensure the water does not contain toxic substances such as heavy metals, etc from volcanic, farming, mining or industrial activities and perhaps these can add an extra level of safety if these are a potential hazard

Measures of quality

  • Hardness:
    • this is a measure of the amount of dissolved calcium and magnesium within the water
    • usually tested with chemical test strips or in the lab as cannot be measured via EC / TDS
  • EC - electrical conductivity
    • expressed in microsiemens per centimeter (μS/cm) at a standardized temperature of 25°C
    • conductivity rises by about 2% for every 1°C increase in temperature hence they also measure temperature and adjust for it
    • EC is a direct proxy for Total Dissolved Solids (TDS) as it is essentially measuring the total concentration of electrolytes / ions dissolved in the water
      • multiplying EC (μS/cm) by a factor between 0.55 and 0.75 (depending on local mineral makeup) estimates TDS in mg/L
      • cannot distinguish between relatively non-toxic ions and toxic heavy metal ions or other ions and ignores non-ionic toxins pathogens
    • low EC (< 50 μS/cm): Indicates very pure or demineralized water (like distilled or rain water) with few ions. It often tastes flat.
    • normal drinking water (50 – 800 μS/cm): typical and safe range for potable water, containing healthy, balanced levels of natural minerals
    • elevated EC (800 – 1,200 μS/cm):
      • noticeable mineral taste (high palatability threshold)
      • under the Australian Drinking Water Guidelines (ADWG), Total Dissolved Solids (TDS) have an aesthetic limit of 600 mg/L, which roughly equates to an EC of about 1,090 μS/cm
    • high EC (> 1,200 μS/cm):
      • water tastes salty or metallic, becomes unpalatable, and may cause scaling or corrosion in pipes
      • obviously drinking water too high in salt (eg. sea water) can be dangerous as it can rapidly rise blood sodium levels and cause convulsions, and coma
  • TDS - total dissolved solids
    • such as calcium, sodium, magnesium, potassium
  • TOC - Total Organic Carbon
    • measures the total amount of organic elements (humic acids, tannins, plastics, pesticides, algae, bacteria, viruses, weed killer, microplastics, PAHs)
    • in devices with UV275, it will be calculated from the UV275 measure
    • ideal drinking water (< 1 to 2 mg/L):
      • typical for well-treated municipal tap water. Low TOC means the water is clean and less likely to support bacterial growth
    • elevated TOC (2 to 5 mg/L):
      • common in untreated surface water or shallow bores.
      • water at this level may have a noticeable earthy smell, a slight yellow tint, or a musty taste
    • high TOC (> 5 mg/L):
      • indicates heavy organic loading.
      • this water requires intensive treatment before it is safe to drink
      • high TOC levels can lead to bacterial regrowth and biofilms inside water storage tanks and household plumbing and in water supplies, when water utilities use chlorine to disinfect water, the chlorine reacts with natural organic matter (TOC) to form harmful chemical byproducts like trihalomethanes (THMs) and haloacetic acids (HAAs) thus it is important to keep TOC low prior to chlorination to prevents these regulated toxins from forming
  • COD - Chemical Oxygen Demand
    • measures the amount of oxygen required to chemically oxidize both organic and inorganic matter in a water sample. While TOC strictly measures organic carbon, COD provides a broader look at everything that can be oxidized, making it a key indicator of overall chemical contamination.
    • in devices with UV275, it will be calculated from the UV275 measure
    • clean, potable drinking water, COD levels should ideally be less than 1 to 2 mg/L
    • a high COD reading in a drinking water source indicates heavy contamination from organic matter (like agricultural runoff or sewage) or oxidisable inorganic chemicals (such as ferrous iron, sulfides, or nitrites)
      • a sudden spike in COD may point to organic fouling — such as decomposing leaf litter or an animal carcass in a rainwater tank, or surface runoff leaching into a shallow bore
    • for typical natural water sources, the COD-to-TOC ratio generally sits between 2.5:1 and 4:1 as it takes more oxygen to break down a compound than just counting its carbon atoms
  • UV275 - UV absorbance at a wavelength of 275nm
    • consumer devices often use UV absorbance at 275nm to estimate organic loading instantly - residual chlorine, humus, macromolecular organic matter, aromatic compounds
    • natural organic matter (like humic acids, tannins from leaves, and aromatic hydrocarbons) absorbs UV light aggressively
    • the device's internal algorithm uses this exact UV275 value to instantly calculate and display the estimated TOC and COD levels
    • monitoring UV absorbance helps estimate how much chlorine is required to safely disinfect the water without creating harmful chemical byproducts
    • measured in Absorbance Units per centimetre (au/cm)
    • ideal/excellent (< 0.05 au/cm):
      • indicates highly purified, well-filtered water with virtually zero organic matter
    • good to average (0.05 – 0.10 au/cm):
      • standard for typical, safe municipal tap water or very clean groundwater
    • poor (> 0.10 au/cm):
      • elevated organic material is present.
      • water may have a distinct colour or odour and needs adequate filtration before drinking.
  • UV254
    • laboratory standard testing traditionally relies on a wavelength of 254 nm — known as UV254
  • Quaternary Ammonium Compounds (QUAT/QAC)
    • usually measured via test strips
    • in the food industry, wash water must have a precise QUAT concentration (usually 200 to 400 ppm) to safely kill pathogens without leaving dangerous chemical residues on food-contact surfaces
    • detectable QUAT reading in your drinking water (which should ideally be 0 ppm) indicates that chemical cleaner, greywater, or industrial runoff has accidentally contaminated the supply
    • a high concentration of them will increase the EC, TDS, TOC, COD readings as they are anionic and they are complex organic molecules made of carbon chains
  • pH
    • electrical meters require calibration with defined buffer solutions prior to use
    • pH is generally not needed to be measured unless it is likely to be contaminated by thermal springs, mining, etc in which case chemical based (eg. litmus type paper) would be the easiest to use in camping (eg. for measuring swimming pool water)
  • microscopy
    • not really practical when camping but could detect amoebae, parasites, etc
  • portable testing for specific heavy metals
    • Multi-Parameter Chemical Test Strips
      • these are similar to standard test strips for swimming pools but with added parameters - they will all expire after a year of so
    • Portable Electrochemical Analyzers (Field Digital Meters)
    • DNA-Based Handheld Fluorimeters
  • you only really need to test for heavy metals if either:
    • you use old lead pipes or fittings
    • you are using rain tank water or bore water
    • the water tastes metallic or is discoloured
    • you are worried about your drinking water especially with young children drinking kit over a long period
  • campers and hikers usually do NOT need to test for it unless they are drinking “non-potable” rain tank water or there are some other unusual circumstance such as ground water from old mining areas (often used mercury for gold mining)
  • “Water Electrolyzer” Scams
    • beware of cheap devices sold online called “water electrolyzers” that feature two metal prongs you drop into a glass of water. When turned on, they rapidly turn tap water into a horrifying sludge of green, black, or brown rust, while leaving distilled water completely clear - this is a scam trick designed to scare consumers. The device does not reveal hidden heavy metals. Instead, it uses the water's normal, healthy conductivity (from sodium and calcium) to pass a current that literally dissolves the iron electrode of the tester itself, creating rust. Distilled water stays clear only because it lacks the conductivity to start the reaction.

Drinking water quality meters

  • basic meters may only test EC and temperature and then calculate the TDS from these values
  • meters with with UV275, will calculate the COD and TOC from the UV275 measure
    • Kactoily 6-in-1 Drinking Water Analyzer
      • can test:
        • UV275 - residual chlorine, humus macromolecular organic matter, aromatic compounds
          • TOC - bacteria, viruses, weed killer, microplastics, PAHs
          • COD - nitrites, organics, sulphide, ferrite
        • Temperature
        • EC - electrical conductivity - ions
          • TDS - total dissolved solids such as calcium, sodium, magnesium, potassium
      • MUST be cleanish water likely to be used for drinking - not waste water
      • requires purified water (distilled water or 100% purified water without minerals) to calibrate each time
      • $AU72
  • chemical-based test strips
    • usually do not test for organic contamination / bacteria / etc
    • Dipstick 9 way heavy metal test strips:
    • SJ WAVE 22 in 1 Water Test Kits:
      • consists of several different test components:
        • 16 in 1 test strips x 125 strips
          • pH, total alkalinity, carbonate, total hardness, chlorine (total, free), cyanuric acid, chlorine dioxide, monopersulfate (MPS) - chemical shock treatment for pools
          • iron, copper, lead
          • nitrate, nitrite, flouride
          • Quaternary Ammonium Compounds (QUAT/QAC)
        • total coliform bacteria tests x 2
        • lead tests x 2
        • 4 in 1 test strips x 10
          • cobalt
          • chromium
          • cadmium
          • sulfite
        • https://www.amazon.com.au/dp/B0G48BW2L6/
    • Hoviran 18 in 1 test strips:
    • Yiffer 21-in-1 Drinking Water Test Strips
    • Aquila 12 Way Heavy Metals Test Strips
  • bacteria testing

Professional rain water tank or bore water testing

  • these are usually NATA-accredited rainwater tank or bore water laboratory tests and users need to send in water samples to the lab
  • eg. https://www.safewaterlab.com.au/shop/p/tank-water-basics
    • tests E. coli & Thermotolerant Coliforms, turbidity, pH, 18 metals & metalloids — Arsenic (As), Silver (Ag), Beryllium (Be), Boron (B), Cadmium (Cd), Chromium (Cr), Cobalt (Co), Copper (Cu), Mercury (Hg), Manganese (Mn), Molybdenum (Mo), Nickel (Ni), Lead (Pb), Antimony (Sb), Selenium (Se), Tin (Sn), Vanadium (V), Zinc (Zn)
australia/water_quality.1788773792.txt.gz · Last modified: 2026/09/07 09:36 by gary1
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