Romsey water quality report

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This report gives you information and updates about water quality sampling and testing at Romsey Recycled Water Plant and nearby waterways.

Update - July 2026

On 20 July 2026, Greater Western Water (GWW) began a controlled emergency release of Class B recycled water into Deep Creek from the Romsey Recycled Water Plant.

This carefully managed, last-resort measure is necessary to maintain safe storage levels at the plant and ensure the continued delivery of essential wastewater services to the community.

Read our full statement at Controlled release of recycled water from Romsey plant.

What we test for

We test four main water quality parameters that are established indicators for protecting the environment and human health:

pH – This is a scale of acidity from 0 to 14. It tells us how acidic or alkaline the water is. More acidic water will have lower pH, while more alkaline solutions have higher pH. Neutral solutions (that aren't acidic or alkaline) usually have a pH of 7.
Suspended solids - Small solid particles that remain in suspension in water. This is an indicator of water quality. The more solids in the water, the less clear the water will be.
E. coli - E. coli are common bacteria, normally found in the gut of warm-blooded animals. There are many types of E. coli bacteria, most of which are harmless. However, some types of E. coli produce toxins (poisons) that can cause gastroenteritis (gastro). Read more at betterhealth.vic.gov.au.
Biological oxygen demand (BOD) - BOD measures the amount of dissolved oxygen used by aerobic microorganisms to break down organic material present in water. It directly affects the amount of dissolved oxygen in rivers and streams. The higher the BOD, the more rapidly oxygen is depleted in the stream, which means there is less oxygen available to aquatic life.

How to read our water quality testing report

The table below shows the quality of recycled water released from Romsey Recycled Water Plant (sampling point 4 on the map below), as assessed by the independent laboratory. Samples are collected from recycled water discharged from the plant's storage lagoons before it mixes with passing stormwater flows. We will publish the results as they become available.

2026 testing results

Parameter	Sampling location	EPA guideline (Class B)	Current result	Sample date	Status
E. coli	4*	<100 Org/L	0	7 September	Pass
Suspended solids	4*	<20mg/L	4	7 September	Pass
pH	4*	6-9	7.8	7 September	Pass
Biological Oxygen Demand (BOD)	4*	<30mg/L	<2	4 September	Pass

*Discharge point (recycled water only)

Green = Pass Class B

Results meet or exceed EPA guidelines for Class B recycled water.

Orange = does not meet Class B (E. coli) guidelines

Results do not meet Class B guidelines for E. coli. If E. coli results exceed 100 org/100ml on two consecutive occasions, we will stop releasing the water and take additional measures to improve water quality. This is a higher standard than previously required by the EPA and demonstrates our commitment to protecting Deep Creek and the community.

Red = Fail Class B

Results do not meet Class B guidelines. GWW will pause the release and take additional measures to improve water quality.

Sometimes sampling point results may be impacted by other water or substances entering Deep Creek outside GWW’s control. For example, during heavy rainfall, stormwater from the stormwater drain upstream of the Romsey release point (sampling point 4) may enter the waterway.