RO, UV and UF get marketed as if they're competing options, but they actually handle different problems, and most good systems combine more than one. The right combination depends almost entirely on what's in your source water to begin with.

RO (Reverse Osmosis): for dissolved solids

RO forces water through a semi-permeable membrane fine enough to block dissolved salts, heavy metals and most dissolved impurities — this is what reduces TDS. It needs electricity to run the pump. If your source water has high TDS (common with borewell or hard groundwater), RO is essential.

UV (Ultraviolet): for microbial safety

UV neutralises bacteria and viruses by exposing water to UV light as it passes through a chamber. It doesn't remove dissolved solids or change taste — it's purely a microbial safeguard, which is exactly why a failed UV lamp gives no taste or flow warning at all.

UF (Ultrafiltration): for particles and cysts, without electricity

UF uses a finer physical membrane than sediment filtration to remove bacteria, cysts and larger particles, without needing power. It doesn't reduce TDS. It's often used as a backup purification stage during power cuts, or as a second microbial safeguard alongside RO+UV. See UF repair for common faults.

So which combination do you actually need?

  • High TDS source water (borewell, hard groundwater): RO is necessary; RO+UV is the common standard combination.
  • Municipal supply with moderate TDS: RO+UV still recommended for microbial safety, since municipal treatment quality can vary.
  • Frequent power cuts: An RO+UV+UF combination gives you a UF fallback for basic purification even when the RO pump can't run.

The mistake worth avoiding

Buying a purifier based on features rather than your actual source water TDS is the most common mistake we see. A system oversized for your water wastes money on stages you don't need; one undersized won't purify properly. A quick source water test — which we do on-site before every installation — settles this in minutes.

Frequently asked questions

Can I add a UV stage to an existing RO-only system?

In most cases yes, provided there's room in the housing and the plumbing supports it — this is a common upgrade rather than needing a full new unit.

Does UF filtration make RO unnecessary?

No — UF doesn't reduce dissolved salts or TDS, so if your source water has high TDS, UF alone won't bring it down to a safe or good-tasting level. The two solve different problems.