3 Harmful Mistakes Every Household Makes That Turn Water Purifiers into “Nests” of Toxins and Bacteria

Many families choose water purifiers to protect their health. However, improper use can lead to serious consequences.

Not Replacing Filter Cartridges Regularly

Every filter cartridge has a certain lifespan. If not replaced on time, it will greatly affect water quality and the lifespan of the machine. Failure to replace cartridges on schedule is the most common mistake in using water purifiers.

Expired cartridges reduce water quality. When the cartridge is overdue but not replaced, contaminants accumulate and may leach back into the filtered water. This makes the output water unsafe, sometimes even more polluted than the input water, directly affecting users’ health.

Moreover, old cartridges also shorten the purifier’s lifespan. Since all components are interconnected, clogged filters slow down water flow, causing unstable operation.

Manufacturers recommend replacing cartridges every 12 months for well water and 18 months for tap water. However, experienced users suggest replacing them earlier. Importantly, never wash or reuse old cartridges, as this diminishes filtering ability and may even worsen contamination.

Installing the Faucet into a Hot Water Pipe

The faucet of a purifier must never be connected to a hot water line. Purifiers are designed to filter water at room temperature. Using hot water can melt pipes, cause serious damage, and quickly wear out the system.

Thinking More Filter Cartridges Mean Better Filtration

More cartridges do not necessarily equal better filtration. An efficient purifier usually has up to 5 cartridges: 3 pre-filters, 1 RO or Nano membrane, and 1 Cation cartridge for areas with high calcium or lime.

After passing through the RO membrane, water becomes pure but loses beneficial minerals. To restore these, manufacturers add machines with 6–9 cartridges, where the extra cartridges only reintroduce minerals rather than removing harmful substances.

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4 Signs You Must Replace the Filter Immediately

1. Filter Cartridge Changes Color
   Pre-filters trap sediments like dirt, sand, rust, calcium, and organic matter. Over time, they turn brown, gray, or black depending on the water source. The darker the color, the more impurities trapped. If still white or lightly yellow, it’s fine. When it darkens and collects thick residue, it must be replaced.

2. Water Flow Slows Down
   If the water stream slows or drips, the filter may be clogged with impurities. Blockages reduce water circulation, causing weak flow.

3. Unusual Noises from the Machine
   When filters clog, unstable flow forces low-pressure valves and solenoid valves to open and close continuously, producing clicking noises.

4. Water Tastes or Smells Strange
   Purified water should be odorless, colorless, and tasteless. If the water has an unusual taste or smell, some filters may be dirty or broken and need replacement.

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How Often Should Filters Be Replaced?

• Filter No. 1 (Pre-filter): Directly contacts source water, trapping dirt and sediments. Replace every 3–6 months depending on water quality.

• Filter No. 2: Usually activated carbon sponge, removes odors, organics, heavy metals, chlorine. Replace every 6–9 months.

• Filter No. 3: Made from PP fibers, filters particles ≥1 micron. Replace every 9–12 months.

• Filter No. 4 (RO Membrane): Removes solids, heavy metal ions, bacteria, toxins. Replace every 24–36 months (higher cost than others).

• Other Functional Filters: Add minerals (potassium, magnesium, phosphorus, calcium) and balance pH. Replace every 12–24 months depending on source water and usage.