NEW PLYMOUTH · OFFICIAL COUNCIL DATA
What's actually in New Plymouth's tap water
New Plymouth District Council released its compliance workbooks for all seven zones it runs, Okato to Urenui - 1,225 chlorine readings, with the quarterly by-products and metals behind them. One honest gap first: the release holds no zone E. coli or coliform results, only the raw river and stream tests, so this page cannot quote the bacteria test the other district pages do. What it does show: chlorine in every zone, fluoride in the four zones on the New Plymouth supply, no lead anywhere, and chlorination by-products above the EWG health guideline in all seven. The free check reads your address.
THE HEADLINE NUMBERS
Seven zones, by-products in every one.
Every zone reading in the release sits inside New Zealand's legal limits. New Plymouth District Council treats its water properly, and its own results show it - the raw Waiwhakaiho River tests show what the plant takes out. The same results show what stays in the water at the tap: trihalomethanes hundreds of times above the EWG health guideline in all seven zones, and fluoride in four of them. Lead was never found. The numbers are below; what you do about them is up to you.
ZONE BY ZONE
What was found in your zone
Chlorine, pH and turbidity three to five times a week in every zone; metals and chlorination by-products each quarter. Zone bacteria results were not part of the release. These are the council's own results. Typical figures are medians; peaks are the highest single sample.
| Zone | Chlorine, typical | THMs, highest sample | Haloacetic acids | Worth knowing |
|---|---|---|---|---|
| Bell Block | 0.85 mg/L | 0.0375 mg/L | 0.006 mg/L | fluoridated; pH peaked at 8.62 against a 7.0-8.5 guideline, 7.7 typical |
| New Plymouth | 0.82 mg/L | 0.0387 mg/L | 0.007 mg/L | fluoridated; chlorine peaked at 1.38 mg/L, the district's highest |
| Tikorangi / Urenui | 0.70 mg/L | 0.0449 mg/L | 0.007 mg/L | fluoridated; the district's THM peak, 299 times the EWG guideline; copper 0.037 mg/L, inside the 1.3 health goal |
| Waitara | 0.82 mg/L | 0.0362 mg/L | 0.006 mg/L | fluoridated; copper never detected, zinc 0.005 mg/L - the lightest metals in the release |
| Inglewood | 0.79 mg/L | 0.0265 mg/L | 0.006 mg/L | not fluoridated; turbidity peaked at 2.32 NTU against a 5 NTU guideline, 0.38 typical |
| Oakura | 0.72 mg/L | 0.0169 mg/L | Not detected | bore-fed and not fluoridated; plant chlorate 0.123 mg/L, inside the 0.8 legal limit |
| Okato | 0.81 mg/L | 0.0322 mg/L | 0.005 mg/L | not fluoridated; zinc 0.038 mg/L, inside the 1.5 guideline |
Source: New Plymouth District Council LGOIMA release CSM26/506186, received September 2026. Chlorine typicals are zone medians of the council's own compliance samples, 1 September 2025 to 17 August 2026 (Oakura and Okato to 14 August) - 1,225 readings, with pH and turbidity from the same samples. THM and HAA figures are the highest per-sample totals from four quarterly rounds, 15 October 2025 to 29 July 2026, summing the quantified species: the release prints no lab totals, and every sample's total against New Zealand's limits sits below one. Haloacetic acid is dichloroacetic acid alone - trichloroacetic acid was reported below a coarse 0.05 mg/L detection limit in every sample - so the figure can only understate; at Oakura neither acid was quantified, so the ceiling is the 0.055 detection-limit sum. Metals: lead, mercury, cadmium, chromium, nickel and antimony below detection in every sample of every zone; only copper and zinc were ever quantified. Fluoride figures are treated water at the New Plymouth plant tap, not reticulation samples. The release contains no zone E. coli or total-coliform results; its only bacteriology is raw source water, before treatment, and none of it reaches a zone row. All zone readings sit inside New Zealand's legal limits. No PFAS or microplastics tests anywhere in the release.
WHAT THIS MEANS FOR YOUR HOUSE
Three things to know.
By-products above the guideline, in every zone
Chlorine meeting natural organic matter forms trihalomethanes and haloacetic acids, and six of the seven zones here are river or stream fed. Tikorangi/Urenui's THM peak of 0.0449 mg/L is 299 times the EWG health guideline, and even bore-fed Oakura's 0.0169 is 112 times it - all inside New Zealand's limits, the highest under a third of the way to them. Dichloroacetic acid reached 0.007 mg/L in the city and Tikorangi/Urenui, 70 times the guideline for that group.
Why treatment matters: the Waiwhakaiho River
The council also tests its raw sources, and the Waiwhakaiho River returned E. coli in 22 of 23 fortnightly samples - 62 to 6,200 per 100 mL, past the lab's 2,420 counting floor - and Lake Mangamahoe the same, past 8,000. That is untreated river and lake water, exactly what a surface source looks like before coagulation, filtration and chlorine, and it is not your tap water. What the release does not hold is the zone E. coli record that would show the tap side of that gap. Closing the gap is the plant's job; what it leaves behind is the point of this page.
Fluoride in four zones, none in three, and no lead
The New Plymouth plant fluoridates, and its treated water carried 0.65 mg/L typically across 24 results, peaking at 0.72 against a 1.5 legal limit - two July 2026 results sat at natural background. Bell Block, the city, Tikorangi/Urenui and Waitara all drink that water; Inglewood, Oakura and Okato have no fluoridation step. Lead was below detection in all 28 zone samples, as were mercury, cadmium, chromium, nickel and antimony. Not one PFAS or microplastics test was run.
YOUR ADDRESS
This is the district picture. Get the report for your home.
The free water check takes about two minutes, and it includes the PDF water report for your address - written from the same release, read for your house.
THE SYSTEM THAT FITS
What we'd fit in New Plymouth.
Fluoride, THMs and the PFAS and microplastics nobody tests for only come out at the kitchen tap with reverse osmosis, and that's the ES60's job. If it's the chlorine in your showers that bothers you, that's a whole-house filter - we supply those by arrangement, so call us on 021 709 370.
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