Ultrafiltration (UF) Membranes: How They Work, Cleaning and Replacement
- Removes particles, bacteria, cloudiness; not salts
- Low flow or rising pressure = clean it
- Flush often; chemical clean per the maker
- Replace when cleaning no longer restores flow
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How UF Works
Water is pushed through thousands of hollow fibres with very fine pores. Particles, bacteria and the cloudy matter in water are held back, while water and dissolved minerals pass through. UF needs no reject water in normal running and works at low pressure.
What UF Removes and Does Not Remove
| Removes | Does not remove |
|---|---|
| Mud, rust and cloudiness | Dissolved salts (TDS) |
| Bacteria and most other microbes | Fluoride and hardness |
| Suspended particles | Dissolved chemicals |
That is why UF is used for treated municipal water and RO for salty boreholes: RO vs UF and municipal UF refill stations.
Signs a UF Membrane Needs Cleaning
- Output flow has dropped at the same inlet pressure.
- Inlet pressure has risen to keep the same flow.
- Water looks less clear after the membrane.
Cleaning Steps
- Flush regularly as the system is designed (forward flush or backwash) to clear the fibres.
- Chemical clean when flushing no longer restores flow, using the cleaning products and steps the membrane maker specifies.
- Rinse well before returning the system to service, and check the water quality.
Protect the membrane with a good sediment pre-filter and change it on schedule: bag and disc filters.
When to Replace
Replace the membrane when cleaning no longer brings flow back or if fibres are damaged (cloudy water after the membrane). Lifespan depends on the water quality and how well it is flushed and pre-filtered.
UF Systems
UF Under Counter System (5 Stage)KSh 17,000
H-Tech 3-in-1 Municipal UF 250LKSh 240,000
H-Tech 3-in-1 Municipal UF 500LKSh 280,000
H-Tech 3-in-1 Municipal UF 1000LKSh 320,000| Product | Price |
|---|---|
| UF Under Counter System (5 Stage) | KSh 17,000 |
| H-Tech 3-in-1 Municipal UF 250L | KSh 240,000 |
| H-Tech 3-in-1 Municipal UF 500L | KSh 280,000 |
| H-Tech 3-in-1 Municipal UF 1000L | KSh 320,000 |
Current listed prices incl. VAT (updated 4 October 2026).
Watch: Starting a water refill business
Frequently asked questions
What does a UF membrane remove?
Particles, cloudiness, bacteria and most other microbes; it does not remove dissolved salts.
How do I know my UF membrane needs cleaning?
Flow drops or inlet pressure rises to keep the same flow.
How do you clean a UF membrane?
Flush it regularly, and chemical-clean it as the maker specifies when flushing no longer restores flow.
When should a UF membrane be replaced?
When cleaning no longer restores flow or fibres are damaged.
Is UF or RO better for borehole water?
RO for salty borehole water; UF for low-salt treated municipal water.