Christchurch water and chlorine: what changed in 2018
Christchurch went without chlorine for decades. Since March 2018 it hasn't. If your shower started smelling different around then, that's why, and it's the easiest part to change.
Hot water lets chlorine go
Christchurch City Council treats the water with sodium hypochlorite, which leaves free chlorine in the pipes. A hot shower is where it comes out.
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: a hot shower on a chlorinated Christchurch supply.
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.
Christchurch and chlorine since 2018
Soft water. Scale is not the Christchurch story. Chlorine is.
| When | What happened | Status | Disinfectant | Source |
|---|---|---|---|---|
| Before 2018 | Most of the city on an unchlorinated supply | Chlorine-free | None | Christchurch City Council |
| March 2018 | The council begins chlorinating | Chlorinated | Free chlorine | Christchurch City Council |
| November 2023 | The regulator declines the council's exemption requests | Chlorinated | Free chlorine | CCC Newsline |
| May 2025 | The regulator restates that residual disinfection is required | Chlorinated | Free chlorine | Reported 11 May 2025 |
| April 2026 | Councillors briefed on an exemption pathway | Chlorinated | Free chlorine | Council agenda, 14 April 2026 |
| October 2026 | Hardness 45 mg/L, soft | Chlorinated | Free chlorine, as sodium hypochlorite | Christchurch City Council |
| Community taps | Chlorine-free taps the council provides | Not chlorinated | None | Christchurch City Council |
Sources as listed, read 3 October 2026. The council's position has moved more than once since 2018, so every row carries its date.
What happens to Christchurch's chlorine inside a Suhae cartridge
Christchurch's sodium hypochlorite leaves free chlorine in the water. In a Suhae cartridge, vitamin C converts that chlorine to chloride as the water passes, before it reaches the spray plate.
The full chemistry, carbon included, is on the chlorine and vitamin C page.
The lab result, read for Christchurch water
Christchurch water carries free chlorine. This is what the lab found when free chlorine met our filter.
Flow
Water moves through a shower head in a fraction of a second, so the vitamin C reacts as it passes.
How long the water spends in the cartridge depends on the flow rate and the cartridge design. Radiance and Nourish measured a mean 5.0 L/min in the SLS test.
Singapore Laboratory Services measured both handshowers at 5.0 litres a minute.
A lower flow gives the same cartridge more contact time. More in 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.
Six samples, all clear
KEWI ran water through the vitamin C filter and sampled it at 1,000, 2,000, 3,000, 4,000, 5,000 and 6,000 litres. Not one sample showed residual chlorine. Certificate IW-230133, 24 April 2023.
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.
Inside the cartridge
The Korea Far Infrared Association tested the ceramic media, certificate KFIA-110.
What it found
A 99.9% reduction in E. coli and S. aureus on the ceramic media after 24 hours of static contact.
The cartridge resists bacteria growing inside it.
Check it yourself
Each figure here has a lab, a certificate number and a date, so you can look it up.
Why it matters in Christchurch
Christchurch runs on free chlorine, and free chlorine is exactly what the KEWI test measured.
What the council says
Christchurch City Council treats the water so it stays safe to drink all the way to your tap. That is the job, and it does it.
Whether you want that chlorine in the steam every morning is a separate question, and it is the one a shower filter answers.
Common questions
Is Christchurch water chlorinated?
Yes. Christchurch City Council has chlorinated the supply since March 2018, and the regulator declined its exemption requests in November 2023. Status as at October 2026. For other cities, the NZ Water Guide has them side by side.
Why does my Christchurch shower smell of chlorine?
Because there is free chlorine in the water, and hot water lets it go as steam. Before 2018 most of the city had none, so the smell is new to a lot of people.
Is vitamin C or carbon better for Christchurch water?
Both work on free chlorine, which is what Christchurch water carries. Carbon holds it on a surface and needs contact time; vitamin C converts it to chloride as the water passes, so it keeps up with a running shower.
Will a shower filter take the chlorine out of Christchurch water?
Ours did in the lab: no residual chlorine detected from 1,000 to 6,000 litres, KEWI certificate IW-230133. Christchurch runs on free chlorine, the form that test measured.
Is Christchurch water hard?
No. The council publishes 45 mg/L, which is soft. Chlorine is the change Christchurch showers have seen, not scale.
Which SUHAE should I buy in Christchurch?
Most people start with Radiance. To keep the head you have, choose Universal. Our New Zealand shower filter comparison puts them side by side.
For Christchurch showers
Take the chlorine out at the shower head, in about two minutes.
Council and regulator dates on this page link to their source.