A filter and a steriliser do two different jobs
This is where most people trip up. They're not the same thing, and one doesn't replace the other.
- A water filter deals with the stuff in your water — sediment, dirt, rust, chlorine, chemicals and taste.
- A UV steriliser deals with what's living in your water — bacteria, viruses and protozoan cysts like Giardia and Cryptosporidium.
A filter won't kill bugs. A steriliser won't clear sediment or chemicals. Run both and you've got the lot covered.
The three threats in your tank water
The water that comes out of your caravan tap has been on a journey. It started at a tap of unknown quality, travelled through your fill hose, sat in your tank for days or weeks, then moved through your plumbing. By the time it hits your glass, it can carry three different threats:
- Physical — sediment, rust, sand, organic matter.
- Chemical — chlorine, chloramine, dissolved metals, taste and odour compounds.
- Biological — bacteria, viruses, and protozoan cysts.
Most caravan filters handle the first two. Almost none handle the third.
Why a filter alone isn't enough
Filtration is a physical process — water passes through a porous medium and anything bigger than the pores gets caught. That works brilliantly for sediment and, paired with carbon, for chemicals. It does not work for biology, for three reasons:
Pore size is a hard limit. Most bacteria are 0.2–2 microns. Viruses are smaller again — 0.02 to 0.3 microns. A 1-micron filter can't remove a 0.3-micron virus, no matter how new or expensive it is.
Carbon claims can mislead. "Bacteriostatic" carbon means silver stops bacteria growing inside the filter itself. It's a maintenance feature for the filter, not a treatment feature for your water.
Biofilm regrows downstream. Even with perfect filtration at the inlet, your 90-litre tank sits in the sun accumulating a slime layer on its inside walls. Once biofilm is established, every glass of water passes over it on the way to the tap.
This is why "I filter my water" is a less complete answer than it sounds.
What UV-C actually does
UV-C is short-wavelength ultraviolet light (200–280 nanometres, peak germicidal activity around 254–265 nm). It doesn't filter anything and doesn't add anything. It shines through the water and wrecks the DNA of anything living in it — so the organism can't reproduce, which means it can't make you sick.
It inactivates the full spectrum of nasties filters miss: E. coli, Giardia, Cryptosporidium, norovirus, rotavirus, hepatitis A. In seconds, at room temperature, no chemicals, no taste change.
LED beats the old mercury lamps in a van, every time: instant-on (no 30–60 second warm-up), no mercury rattling around on corrugations, low 12V draw, and no lamp to replace.
The two-stage system: filter first, then UV-C
The order matters. UV-C light has to shine through the water to reach the bugs — cloudy, sediment-heavy water blocks the light and pathogens hide behind the grit.
So a serious caravan water system runs in two stages:
Stage 1 — Filtration. A sediment + carbon filter strips out particles down to 0.5 micron, removes chlorine and improves taste. The Vankor Pro Flow 12 does this at 12 L/min so you don't cop a pressure drop in the shower.
Weighing up filters? Our best caravan water filter buying guide walks through micron rating, flow rate, staging and cost — so you can judge any filter on the shelf.
Stage 2 — UV-C sterilisation. The clear, filtered water passes through a UV-C LED reactor that disrupts the DNA of anything living. The Vankor UV-C LED Water Steriliser is lab-tested to knock out 99.99% of E. coli, runs on 12V, and has a 10,000-hour LED — nothing to refill or replace.
It's the same logic municipal water treatment plants use, scaled down for a caravan and powered off your 12V system.
So — do you need both?
Match it to where your water comes from:
| Where you fill up | What you need |
|---|---|
| Town / mains water only | Water filter (Pro Flow 12) |
| Tanks, bores, creeks, remote taps | Filter + UV steriliser |
| Mixed — you tour everywhere | Filter + UV steriliser (the bundle) |
If you free-camp, tour remote, or top up from wherever you can, lean towards both. It's cheap insurance against a ruined trip.
The easy way to do it
Rather not piece it together? The Caravan Water System Kit pairs the Pro Flow 12 and the UV-C steriliser in one go — full two-stage protection, ready to fit. Filter first, sterilise second, drink.
FAQs
Will UV-C change the taste of my water? No. It only damages the genetic material of pathogens. It adds nothing and doesn't change taste, pH or mineral content.
Do I still need a filter if I have UV-C? Yes. UV-C only inactivates pathogens — it doesn't remove sediment, chlorine or metals. And the UV works better when the water's already clear. Filter first, sterilise second.
Will UV-C work on tank water that's been sitting for weeks? Yes — this is exactly what UV-C is best at. Stored water grows biofilm and bacteria; UV-C sorts it out at the point of use.
What about bore water? UV-C handles the biology. Bore water often carries iron, minerals or hardness too — you'll want a filter in front of the UV. See our bore water guide for the full picture.
Can I fit it myself? Yes. Both fit inline with standard 12mm push-fit fittings — no plumber, no electrician. The steriliser runs off 12V.
Do I still need to boil water? The filter clears sediment and chemicals, and the UV-C is lab-tested to kill 99.99% of E. coli — together they cover both particles and bugs. If you're ever unsure about a really dodgy source, boiling is still the failsafe.
Two ways to get started:
→ Vankor Pro Flow 12 Water Filter — stage one: sediment, chlorine, taste, PFAS.
→ Vankor UV-C LED Water Steriliser — stage two: bacteria, viruses, protozoa.
Or grab the complete two-stage kit and set both up at once.
Vankor builds gear for Australian caravan, camping and off-grid life. Fit once, forget about it. Made to a standard we'd stake our own trip on.