Water quality is crucial for both residential and commercial use. While mains water supply is treated to remove harmful bacteria, some microorganisms can still enter domestic systems. If these bacteria multiply, they can compromise water safety. One of the most effective ways to monitor microbial levels in water is through Total Viable Count (TVC) testing.
What is Total Viable Count (TVC)?
Total Viable Count (TVC) is a microbiological test that estimates the number of live microorganisms – such as bacteria, yeast, and mould – present in a water sample. It provides a broad indication of water contamination and overall quality.
TVC is sometimes called aerobic colony count (ACC) and is different from Total Bacteria Count (TBC). While TVC measures only viable cells capable of growing into colonies, TBC includes both live and dead cells.
How is TVC Measured in Water Testing?
TVC testing involves incubating water samples under specific conditions to assess microbial growth. The incubation temperature depends on the sample type:
- 22˚C incubation (for 24 hours) – Measures bacteria growing at ambient temperature, usually harmless.
- 37˚C incubation (for 24 hours) – Measures bacteria that thrive at body temperature and may pose health risks.
- 30˚C incubation (for 48 hours) – Used for cooling tower systems to identify potentially harmful bacteria.
This non-selective test captures a wide range of microorganisms, unlike targeted tests for Legionella or Pseudomonas aeruginosa, which require specific growth media.
Why is TVC Testing Important?
Regular TVC testing is essential for identifying changes in water quality and ensuring compliance with safety standards. A high TVC count (e.g., 10,000 cfu/ml) may indicate:
- Biofilm formation in pipes or tanks
- Stagnant or poor-quality drinking water
- Ineffective water treatment or filtration
- Need for additional microbial analysis
While there are no strict regulatory limits for TVC in drinking water, the general guideline is “no significant increase” from the mains supply. Businesses should conduct regular tests to establish a baseline and detect deviations early.
Who Should Conduct TVC Testing?
Total Viable Count testing is crucial across various industries, including:
- Drinking water systems (homes, offices, hotels, hospitals)
- Manufacturing and food processing (where water quality affects product safety)
- Healthcare and pharmaceuticals (to prevent microbial contamination)
- Industrial cooling and heating systems (to control biofilm formation)
Routine water testing helps businesses comply with health regulations, maintain hygiene standards, and prevent costly system failures.
Controlling TVC Levels in Water Systems
Preventive measures can help keep TVC levels in check:
- Regular system maintenance – Clean and disinfect water tanks, pipes, and filters.
- Temperature control – Keep hot water above 60˚C and cold water below 20˚C to limit bacterial growth.
- Chlorination and disinfection – Use effective biocides to treat water when necessary.
- Monitoring and risk assessment – Establish a routine testing schedule to detect trends and take corrective action.
By implementing these measures, businesses can ensure safe water quality and compliance with industry standards.
Need Expert Water Testing?
For reliable Total Viable Count testing, contact Test Needs:
Phone: 03 9115 8105
Email: info@testneeds.com.au
Regular TVC testing helps protect public health, maintain system efficiency, and ensure compliance with Australian water quality standards. Schedule your test today!
