Ensuring Safe Drinking Water: A Guide to Water Testing

Clean drinking water is fundamental to health, especially in emergency situations or remote areas where infrastructure may be compromised. Total Dissolved Solids (TDS) testing is one method to quickly assess water quality, but it is only one part of a broader water safety framework. This article outlines the relevant standards, what to test for, how to test drinking water safely, and who is responsible for testing in Australia and New Zealand.

Drinking Water Standards in Australia and New Zealand

Both Australia and New Zealand have robust national guidelines for drinking water safety:

• Australia: The Australian Drinking Water Guidelines (ADWG), developed by the National Health and Medical Research Council (NHMRC) and the Department of Health, outline acceptable levels for microbial, chemical, and physical characteristics in water. These guidelines are not legally binding, but they are widely adopted by water authorities and referenced in regulation.

• New Zealand: Drinking water quality is regulated under the Health (Drinking Water) Amendment Act 2007and guided by the Drinking-water Standards for New Zealand (DWSNZ), published by Taumata Arowai—the country’s dedicated water services regulator.

These standards set limits for contaminants including bacteria (like E. coli), heavy metals (like lead and arsenic), nitrates, turbidity, and more.

What Should You Test For?

Depending on your water source—whether it's rainwater, groundwater, surface water, or desalinated seawater—the following tests may be relevant:

• Microbiological Contaminants:

  • E. coli: An indicator of faecal contamination; must be zero in drinking water.

  • Total coliforms: Not necessarily harmful but indicate potential contamination.

• Chemical Contaminants:

  • Heavy metals: Lead, arsenic, mercury, and copper can leach from pipes or be present naturally.

  • Nitrates and Nitrites: Common in agricultural runoff, can be dangerous to infants.

  • Fluoride and Chlorine: Often added for public health reasons but must stay within safe limits.

• Physical Parameters:

  • pH: Ideally between 6.5–8.5.

  • Turbidity: Measures cloudiness; high turbidity can harbour pathogens.

  • TDS (Total Dissolved Solids): Indicates the total concentration of dissolved substances in water. High TDS may affect taste or signal contamination.

TDS Testing in Practice

TDS is a useful parameter for monitoring changes in water quality and is especially helpful for systems using reverse osmosis or desalination. TDS does not identify specific contaminants, but it provides a quick indication of overall dissolved solids concentration, helping to:

• Verify system performance

• Detect unusual increases in dissolved substances

• Prompt further testing if results are outside normal range

Who Can Test Drinking Water?

Water testing can be conducted by:

• Accredited Laboratories: In Australia, NATA (National Association of Testing Authorities) accredits labs for water quality testing. In New Zealand, IANZ (International Accreditation New Zealand) provides equivalent certification.

• Local Health Authorities: State and regional departments of health may offer testing services or advice for household and community systems.

• Private Water Consultants: Environmental and engineering firms can conduct site assessments, sample collection, and detailed testing.

• DIY Field Test Kits: Useful for preliminary screening, particularly for pH, chlorine, and bacteria. 

A Basic Testing Guide for System Owners

Here’s how to get started with basic water testing if you rely on a personal or community-level treatment system:

1. Check Your TDS Meter

   • Ensure the TDS reading is within safe limits: below 500 ppm (mg/L) for general drinking water, and ideally under 250 ppm for taste.

   • A sudden spike in TDS may indicate a membrane failure or contaminated source water.

2. Visual Inspection

   • Check for cloudiness, discoloration, or unusual odours. Water should be clear and free of debris.

3. Use a Field Test Kit

   • Purchase a kit that includes tests for pH, chlorine, E. coli, and nitrate.

   • Follow manufacturer instructions to collect a sample and interpret the results.

   • Ideal pH range is 6.5–8.5. Any chlorine residue should be under 5 mg/L.

4. Record and Compare

   • Keep a simple log of your readings (TDS, pH, etc.) to monitor trends over time.

   • If you notice consistent abnormalities, consider sending a sample to an accredited lab.

5. After Natural Disasters

   • Always test your source water after floods, storms, or volcanic activity. These events can introduce contaminants even if the water appears clear.

6. Routine Testing Schedule

   • Frequent Use: For daily-use systems, conduct basic tests weekly and a lab test every 3–6 months.

   • Occasional Use or Standby: Test before and after each deployment.

Final Thoughts

Safe drinking water requires more than just clear water and good taste. Regular testing is essential to protect health and ensure system performance. Built-in tools like TDS meters offer helpful real-time insights, but they should be paired with periodic microbial and chemical testing to meet national safety standards.

At LEDI, we equip our AquaGen systems with real-time TDS monitoring and encourage users to follow best practices in water safety. If you need help interpreting results or finding a local testing provider, feel free to contact us for support.

Download the factsheet here