Chlorine, vitamin C and your shower
New Zealand water is chlorinated on purpose. In a hot shower that chlorine comes off as steam, and vitamin C converts it before it reaches you.
Why you smell chlorine in the shower and not in a glass
New Zealand suppliers disinfect with free chlorine. How much of it reaches your nose depends on the water temperature and what the water passed through.
In a hot shower. Some of it leaves on the way down.
Free chlorine is more volatile
Free chlorine can move from water into the air, which can make its smell more noticeable in a hot shower.
Where you will meet it: every town supply in New Zealand.
With the filter. Same recess, same spray, nothing leaving.
Vitamin C converts it first
Vitamin C turns free chlorine into chloride inside the cartridge, before the water reaches the spray plate. Nothing is left to come off in the steam.
Where you will meet it: any SUHAE shower head, or behind your own head with Universal.
What your supplier uses
Christchurch publishes 45 mg/L, which is soft. Across most of New Zealand, the thing in your shower is chlorine, not scale.
| City | Hardness | Reads as | Disinfectant | Source |
|---|---|---|---|---|
| Christchurch | 45 | Mostly soft | Free chlorine, since March 2018 | Christchurch City Council |
| Auckland | not published | Soft to moderately hard | Free chlorine, about 0.6 to 0.8 mg/L at Forrest Hill | Watercare |
| Wellington city | 18 to 45, by plant | Soft | Free chlorine, at least about 0.4 mg/L across the network | Tiaki Wai |
| Hutt Valley and Porirua | 18 to 45, by plant | Soft | Free chlorine | Tiaki Wai |
| Queenstown and Wānaka | not obtained | Unknown | Free chlorine, permanently | Otago Daily Times |
| Everywhere else on town water | varies by supply | Mostly soft | Free chlorine | Taumata Arowai |
| Tank and bore water | varies | Varies | Usually none | Water New Zealand |
Sources, read 3 October 2026: Christchurch City Council; Watercare (water hardness page and Ardmore chlorine sheet, 11 June 2024); Tiaki Wai, which took over from Wellington Water on 1 July 2026 (plant means as at 25 November 2022); Taumata Arowai (official information response, 9 August 2024); Water New Zealand. Under 100 mg/L counts as soft in New Zealand. City figures are a guide, and your street can differ.
Adsorption and chemical reduction work differently
The mechanism decides how a filter copes with the free chlorine in New Zealand water.
Left, adsorption. Held on a surface until the surface runs out of room. Right, chemical reduction. Converted, and the acid is used up doing it.
A Vita cartridge in section. The media is consumed rather than filled.
Adsorption
Activated carbon adsorbs compounds onto its internal surface area.
It is physical rather than chemical, and the carbon fills up. That is why carbon cartridges are rated in litres.
Carbon is widely used for free chlorine. How well it keeps up depends on contact time, and a shower gives it very little.
Chemical reduction
Ascorbic acid, which is vitamin C, acts as a reducing agent and reacts with chlorine compounds.
This is a chemical reaction rather than adsorption onto a surface.
The ascorbic acid is consumed through use, which is why the cartridge requires replacement.
That is the media in Vitae Infusion.
What the published tests show
Three reports, each with a named lab, a method and a date.
Contact time
Water passes through a shower head in a fraction of a second, so the media has to work as it moves.
Contact time depends on the installed flow rate and cartridge design. Radiance and Nourish recorded a mean flow rate of 5.0 L/min in the cited SLS test.
Both handshowers were measured at 5.0 litres a minute by Singapore Laboratory Services.
A lower flow rate can increase contact time within the same cartridge geometry. See the Aera Flow measurements and test scope.
Singapore Laboratory Services, report 22608188-CLC, 19 March 2026. 5.0 litres a minute, tested to AS/NZS 3662:2013.
The test conditions, in full
The chlorine result comes from the Korea Environment and Water Works Institute, certificate IW-230133, 24 April 2023. Water ran through the vitamin C filter and was sampled at 1,000, 2,000, 3,000, 4,000, 5,000 and 6,000 litres. Residual chlorine was not detected at any of them.
The flow figure is the mean across 1.5, 2.5, 3.5, 4.5 and 5.0 bar, measured under clause 5.1 and appendix B of the standard, and it sits in the top efficiency band of 5 litres a minute or less. The laboratory is SAC-SINGLAS accredited.
The report covers the Radiance handshower in chrome and black and the Nourish handshower in chrome. The plate is a patented design with triangular openings around 0.3 mm across, up to ten times smaller than a conventional shower hole, which is how it holds the spray up on less water.
Media hygiene
The ceramic media was tested by the Korea Far Infrared Association, certificate KFIA-110.
What that test covers
The test recorded a 99.9% reduction in E. coli and S. aureus on the ceramic media after 24 hours of static contact.
The filter media is tested to resist bacteria growing inside the cartridge.
Why we print the numbers
Every figure on this page has a lab name, a certificate number and a date beside it, so you can check it yourself.
Why it matters in New Zealand
No New Zealand supplier is on record using chloramine. Free chlorine is what is in your water, and free chlorine is what these tests measured.
What your supplier says
Watercare says its treatment plants meet the Taumata Arowai drinking water rules. Your tap water is safe to drink, and it is chlorinated so it stays that way.
The chlorine is there on purpose, and it does its job in the pipes. Whether you want it in the steam for ten minutes every morning is a different question, and that one is yours.
Common questions
Does NZ tap water have chlorine in it?
Yes, if you are on town water. New Zealand suppliers keep a free chlorine residual in the pipes, and Taumata Arowai has no record of any of them using chloramine. Christchurch has been chlorinated since March 2018. Tank and bore water is usually not chlorinated. For your own supplier, the NZ Water Guide has it city by city.
How do I tell if my tap water is chlorinated?
Look at who sends the water bill: a council or council-owned supplier means chlorinated town water. To see it for yourself, a free-chlorine test strip from a pool shop gives you a reading in about a minute.
Is vitamin C better than carbon?
They work differently. Carbon holds free chlorine on its surface and needs contact time. Vitamin C converts it into chloride as the water passes, which suits a shower, where the water moves fast.
Do shower water filters really work?
A good one does, and you can check ours. In the KEWI test our vitamin C filter left no detectable chlorine at any sample point from 1,000 to 6,000 litres, certificate IW-230133.
Do I have hard water?
Probably not. Christchurch publishes 45 mg/L and Wellington's plants run 18 to 45, both soft. Watercare describes Auckland's sources as soft to moderately hard. In most of New Zealand the thing in your shower is chlorine, not scale.
What is the best shower filter in New Zealand?
Use our New Zealand shower filter comparison to compare media, lab evidence, fit and running cost in NZ dollars, ours included.
Start with your own water
Check what your supplier uses, then take the chlorine out at the shower head.
Every supplier figure on this page links to its source.