Water Filter for Home: Jug, Candle, UV or RO, Which to Buy
Buy the filter that matches what’s wrong with your water, not the one with the most stages on the box. A carbon jug fixes taste and chlorine, a ceramic candle stops most germs, UV kills germs in clear water, and only RO takes out salts and arsenic. The one rule that beats every brand choice: a cartridge left unchanged past its life can make water worse than no filter at all.
Quick facts
- Jug or tap carbon filter: taste, smell, chlorine; not germs, not salts
- Ceramic candle (matka filter): bacteria and parasites; not viruses reliably, not salts
- UV purifier: kills germs; needs clear water and electricity; no effect on salts
- RO purifier: salts, hardness, arsenic, most germs; wastes water, costs most
- TDS meter: a taste guide, not a safety test
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Which water filter is best for home? Start with your water, not the shop
A salesman in a shop will usually start with the most expensive RO unit on the wall. Before you let him, answer three questions about your own tap.
- Does it taste salty, bitter or leave thick scale? Simmer 1 litre in a clean steel pot on low heat until only a few spoonfuls remain, switch off and let the rest dry in the warm pot. A thick white or brown crust suggests high dissolved salts. A thin film is normal.
- Is it cloudy or muddy? Stand a clear glass for 1 hour. Sediment at the bottom means you need a sediment prefilter whatever else you buy.
- Where does it come from? City supply, your own bore, a tanker or a shared overhead tank? Bore and tanker water carry the widest range of problems.
- Get one lab test if you can. A basic panel for bacteria, TDS, arsenic, nitrate and hardness from a public health engineering or water authority lab settles the question for years.
Then match. Germs only means candle, UV or boiling. Salts or arsenic means RO. Just a chlorine smell from a city supply means a carbon filter is plenty.
Jug, candle, UV or RO: what each filter class really does
| Filter class | Removes | Leaves in | Needs |
|---|---|---|---|
| Carbon jug or tap | Chlorine, smell, some pesticides | Germs, salts, arsenic | Cartridge change on time |
| Ceramic candle | Bacteria, parasites, mud | Viruses (partly), salts | Weekly scrub |
| UV | Kills germs | Salts, metals, mud | Clear water, power, lamp change |
| RO (usually with carbon and UV) | Salts, arsenic, hardness, germs | Very little | Power, pressure, service |
Carbon: the taste fixer
Activated carbon is charcoal treated to be full of tiny pores. Chlorine and smelly compounds stick to it. That’s why a jug makes city water taste nicer. But a carbon block does nothing to kill germs, and once its pores fill, it stops working without any warning sign. Charcoal water filter side effects are mostly about this: a saturated, wet carbon block can grow bacteria inside it.
Ceramic candle: the old reliable
The two-pot steel or plastic filter with white ceramic candles is still one of the best value buys in South Asia. The fine pores hold back bacteria and parasites like giardia. Viruses are small enough that some can pass, so in a flood or a known outbreak, boil as well. Scrub the candle every week under running water with a clean soft brush, never soap, and replace it when it cracks or when scrubbing has worn it thin.
UV: germs only, and only in clear water
A UV lamp damages the genetic material of germs as water flows past. Mud shields germs from the light, so UV needs clear water or a prefilter. It needs power too, so in load shedding hours, water that passed through a dead lamp was not treated. The lamp dims with age and is usually replaced on the maker’s schedule even if it still glows.
RO: the heavy tool
Reverse osmosis is covered fully in is RO water dead water. In short: it’s the only home class that reliably removes salts and arsenic, it’s safe to drink long term, and it throws away a lot of water. Put the reject pipe into a bucket for mopping; RO waste water for plants explains which plants tolerate it.
Dangers of not changing a water filter
This is the part nobody tells you in the shop. Every filter traps things. When it’s full, three things happen.
- It stops removing. A carbon block past its life lets chlorine and smells straight through.
- It grows things. Warm, wet, dark and full of trapped organic matter: that’s a perfect home for bacteria. Water can come out with more germs than it went in with.
- It can release what it caught. An overloaded filter can shed trapped material back into the water.
Write the fitting date on the cartridge with a marker. Set a phone reminder a week before the maker’s change date. If you can’t keep up with changes or service visits, a simpler system you’ll actually maintain (a candle filter plus boiling) beats an RO unit that’s two years overdue.
An overdue cartridge isn’t neutral. It’s a small, warm swamp in your water line.
How to read a TDS number without being fooled
TDS (total dissolved solids) meters are sold cheaply and used in almost every sales demonstration. They measure how well water conducts electricity, which rises with dissolved salts. Useful for two things: judging taste and checking that an RO membrane is still working (the purified water’s reading should stay low and steady).
What TDS can’t tell you: whether there are bacteria, viruses, arsenic, lead, nitrate or pesticides at harmful levels. Water at 80 can be full of germs. Water at 400 can be perfectly safe. The water authority guidance is mainly about taste: WHO notes water tastes good below about 600 mg/L and turns unpleasant above about 1,000 mg/L.
Myth: the lowest TDS is the healthiest water
Sales demos often show tap water at 300, then RO at 20, as if the lower number were a health score. It isn’t. It only shows fewer dissolved salts. Chasing a very low number just makes the water taste flat and uses more membrane.
Did you know? A ceramic candle’s pores are so small that a single candle takes hours to fill the bottom pot, which is exactly why it works. Slow water is filtered water; a candle that suddenly runs fast is cracked.
No home filter makes sewage-contaminated or flood water safe on its own; in floods, boil as well, or use a sealed supply. A filter can’t tell you your water is safe, and neither can a salesman’s meter: only a lab test proves it. If someone in the family gets repeated diarrhoea, jaundice or typhoid, test the water and see a doctor, and keep a sick child drinking ORS until you do. Anyone on dialysis or with kidney disease should ask their doctor which water to drink.
More practical home guides sit under Desi Remedies.
Water filter questions, answered
Are water filters worth it?
Yes, when the filter class matches the problem and you keep up with changes. A carbon jug for chlorine taste, a candle or UV for germs, RO for salts and arsenic. A mismatched or neglected filter is money wasted.
What is the best water filter for home in Pakistan?
There’s no single best; it depends on your water. In salty or arsenic areas, RO. On a decent city supply with a germ worry, a UV or ceramic candle filter plus a clean tank is often enough.
Water filter vs water purifier: what’s the difference?
In shops, “filter” usually means a physical barrier like carbon or ceramic, and “purifier” means something that kills or removes germs and salts, like UV or RO. The labels are loose, so check which classes are inside.
Is filtered water safer than boiled water?
For germs, boiling is at least as good as any home filter. Filters beat boiling only for things boiling can’t touch: chlorine taste (carbon) and salts or arsenic (RO).
Do charcoal water filters have side effects?
Not from the charcoal itself. The risk comes from an old block that has filled up and started growing bacteria, so change it on time.
How often should a ceramic candle be cleaned and changed?
Scrub it weekly under running water with a soft brush and no soap. Replace it when it cracks, when water runs through suspiciously fast, or when scrubbing has visibly worn it down.
Does a UV water purifier work without electricity?
No. Water that flows through during a power cut is untreated. Store treated water for load shedding hours or boil as a backup.
Which water filter removes arsenic?
Among common home systems, RO is the reliable one. Carbon, ceramic and UV do not remove arsenic. Confirm with a lab test on the filtered water.
Which filter removes microplastics?
Fine ceramic and RO membranes hold back most particles of that size. The health effect of the tiny amounts in drinking water isn’t yet known, so it shouldn’t be the main reason to buy.
Is a TDS meter enough to check water safety?
No. It measures dissolved salts only. Germs, arsenic, lead and nitrate can be present at any TDS reading.