Commercial water filtration: a maintenance checklist
Commercial filtration fails in two ways. It stops working, which affects your product. Or it stops being documented, which affects your inspection.
This checklist covers both. Adapt the intervals to your actual throughput — everything below assumes a moderately busy site, and a genuinely busy one will need to move faster.
Weekly
Check the flow meter reading against the cartridge's rated capacity, and note it.
Look at the installation. Leaks, drips, corrosion at fittings, anything that has been knocked.
Taste-check the output where water is an ingredient. It is not a measurement, but it catches problems early.
Check the softener salt level if you have one, and top up before it runs low rather than after.
Monthly
Test hardness on the treated line and record it. On a softener this is the single check that proves it is still working.
Check the pressure differential across filter housings if gauges are fitted.
On RO, compare feed TDS against product TDS and record the rejection ratio. A drifting ratio is the earliest warning of a failing membrane.
Confirm the service log is actually being filled in. It usually is not.
Every three to six months
Replace cartridges according to volume, not date. The flow meter reading is what should trigger this.
Sanitise housings at each cartridge change.
Check and grease O-rings.
Operate every isolation and bypass valve so they do not seize.
Annually
Full service by a competent engineer.
Replace UV lamps if fitted, regardless of whether they still light — output decays long before the lamp fails.
Review whether the specification still fits the business. Sites grow, menus change, and equipment sized three years ago is often undersized now.
Check backflow protection is intact and appropriate to the fluid category on the premises.
Renew the service contract and confirm response times.
Records to keep
What is installed, where, and its specification.
Every cartridge change, with date, who did it and the meter reading at the time.
Test results — hardness, TDS, and any microbiological testing.
Service visit reports and engineer details.
Any water quality complaint and what was done about it.
In a food business these form part of your food safety management documentation. Keep them together, keep them current, and keep them somewhere the person covering for you can find them.