How to Get the Most from Your RO Membrane in Australia
August 25, 20242 min read
Your RO membrane is the most important and most expensive component in your reverse osmosis system. Here’s how to protect it and get the most from it in Australian conditions.
The RO membrane is a semi-permeable barrier that blocks dissolved contaminants — fluoride, heavy metals, nitrates, TDS — while allowing water molecules through. It operates under mains water pressure (typically 40–80 psi in Australian homes). Contaminants are flushed to drain as wastewater; filtered water passes through to the storage tank.
What Shortens RO Membrane Life
Chlorine exposure: Chlorine degrades the membrane material over time. This is why the pre-carbon filter (which removes chlorine before the membrane) must be replaced on schedule — every 6–12 months. A failed pre-carbon filter is the most common cause of premature membrane failure.
Low water pressure: RO membranes need adequate pressure to function efficiently. Australian mains pressure is typically 40–80 psi — most systems operate well in this range. If your pressure is below 40 psi (common in some rural areas or older homes), a booster pump may be needed.
High TDS input: Very high TDS water (bore water, some regional supplies) puts more load on the membrane. In high-TDS areas, replace the membrane at the shorter end of the service life range.
Skipping pre-filter replacement: The sediment and carbon pre-filters protect the membrane. Replace them on schedule regardless of whether the membrane appears to be performing well.
Maintenance Schedule for Australian Conditions
Component
Replace Every
Notes
Sediment pre-filter
6–12 months
More frequently in high-sediment areas
Carbon pre-filter
6–12 months
Critical — protects membrane from chlorine
RO membrane
2–3 years
Replace sooner if TDS rejection drops below 85%
Post carbon filter
6–12 months
Polishes taste before the tap
How to Monitor Membrane Performance
A TDS (Total Dissolved Solids) meter is the most practical way to monitor membrane performance. Measure TDS of your input water and your filtered output. A healthy RO membrane rejects 90–99% of TDS. If rejection drops below 85%, the membrane needs replacing. TDS meters are inexpensive and available from us — call us on 1800 789 781.
Frequently Asked Questions
How long does an RO membrane last in Australia?
2–3 years with proper pre-filter maintenance. In hard water areas (Perth, Adelaide) or high-TDS bore water, replace at 2 years. Monitor with a TDS meter — replace when rejection drops below 85%.
What happens if I don’t replace my pre-carbon filter on time?
Chlorine passes through to the RO membrane and degrades it — this is the most common cause of premature membrane failure. Replace pre-filters every 6–12 months without exception. Browse our replacement cartridge range.
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