Reverse osmosis water treatment system with stainless tanks and pumps

RO water: TDS creeping up or bad taste

Measure before replacing anything: compare feed and product TDS to get the membrane's rejection, and compare a first draw with a flushed sample to separate normal TDS creep from a real failure. Bad taste with good rejection usually points to the post filter, the tank or stagnant water; poor rejection points to the membrane, the carbon pre-filters that protect it, low pressure or a plumbing mistake.

Cross-checked ~45 min easyBrands: APEC, iSpring, All under-sink RO

Before you start

Close the feed valve and relieve pressure before opening housings
Sanitizer water is not drinkable: flush completely
Booster-pump systems: unplug the transformer before servicing the pump

Diagnostic steps

Unlock all 9 steps with expected values

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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