Analyzing the data of the population connected to sewerage with primary treatment in Australia from 2013 to 2023, a clear downward trend is observed. In 2023, the population connected stood at 15.48 units. Over the years, there has been a significant percentage variation with plunges in 2018 (-14.3%) and a continuous decline in recent years, showing a year-on-year variation of -3.67% in 2023. The past 5 years exhibited a slight average annual decline with a CAGR of -1.81%. The forecasted data from 2024 onward indicates a continued decline, expected to reach 12.44 units by 2028 with a forecasted 5-year CAGR of -3.47% and a forecasted 5-year growth rate of -16.17%.

Future trends to watch for:

The effect of policy changes or new infrastructure investments aimed at improving wastewater treatment and how they might slow down or reverse the decline.
Population growth and urbanization which might strain the existing sewerage systems, necessitating upgrades or expansions.
Technological advancements in wastewater treatment that could impact the number of populations connected to primary treatment.