Hamilton City Council
Te kaunihera o Kirikiriroa
October 2025
The boil water notice for properties in north-east Hamilton has been lifted as of 12pm today and the water is safe to drink.
Hamilton City Council has had three days of water tests that are clear of E. coli from the Rototuna reservoir and other sampling sites around the city.
This means drinking water for properties in Rototuna, Flagstaff, and parts of Queenwood in Hamilton, and Gordonton and Puketaha in Waikato District, no longer needs to be boiled for any purpose.
There are some steps you need to take before you start to use tap water as you normally would.
For properties on supplied directly from the network (i.e. no water tank):
For properties on trickle feed supply or a water storage tank
On Saturday 4 October we received a single positive result for E. coli in the Rototuna Reservoir. With advice from Taumata Arowai and the Ministry of Health, a boil water notice was issued for those in the Rototuna supply zone. There have been no other positive tests at the site, and testing at other reservoirs has not detected E. coli. The notice applies to around 12,000 properties and 29,000 residents in Rototuna.
If you live in the Rototuna water supply zone, you must boil tap water before using it for drinking, cooking, or brushing teeth. More information, including FAQs and a list of affected streets are below.
We will continue to update this page as results are returned.
Water testing is again clear of E. coli at Rototuna Reservoir and other key testing sites, for the second day in a row.
The boil water notice remains in place for the Rototuna water supply zone until at least tomorrow, as three consecutive days of clear testing are required before a notice can be lifted.
See the map below for the affected area. No other parts of Hamilton are affected.
Test results at the Rototuna Reservoir and other sample sites around the city are clear of any E. coli presence.
A boil water notice was issued yesterday after a single confirmed test yesterday morning (Saturday 4 October) showed the presence of E. coli in a water sample from the Rototuna reservoir. Today’s test results showed no E. coli present in samples at the site, or elsewhere in the network.
The boil water notice will remain in place until at least Tuesday as three consecutive clear tests are required before a notice can be lifted.
Boil water notice and information for food businesses in the Rototuna water supply zone (see map)
On Saturday 4 October 2025, Hamilton City Council issued a boil water notice following a positive test for E. Coli during routing testing at the Rototuna Reservoir.
The notice will be in place for a minimum of three days, or until three consecutive days of compliant test results.
The positive test was from a single test. Further testing is underway at the reservoir and throughout the network.
What this means for food businesses
A boil water notice doesn’t mean your business can not continue to operate, providing you can meet the steps needed to operate safely.
A boil water notice means that the tap water supply may be contaminated with harmful bacteria like E. coli, and it’s not safe to use without boiling first. As a food business owner, this has important implications for how you operate.
Hamilton City Council has established an Incident Management Team as we investigate this issue, and we are working closely with the water regulator Taumata Arowai, the Ministry of Health and other agencies.
Click on the image below to view it larger.
We have issued a boil water notice for the Rototuna water supply zone as a single positive E. coli test result was confirmed in routine testing this morning.
The area affected is shown in the attached map (this has now been updated above).
We immediately established an Incident Management Team, notified the regulator Taumata Arowai, and are conducting further tests and checks across our network.
Until notified, Rototuna residents are advised to boil water before using it for:
Electric jugs with a cut-off switch can be used as long as they are full – allow the water to come to the boil and wait for it to switch off (do not hold the switch down to increase the boiling time). Water can also be placed in a clean metal pan and brought to a rolling boil for one minute. Boiled water should be covered and allowed to cool in the same container.
People with severely compromised immune systems, infants, pregnant women, and some elderly may be at increased risk. These people should seek advice about drinking water from their health care providers. If you have specific health concerns, consult your doctor or Healthline 0800 611 116.
If you have other houses or tenants on your property please advise them of the contents of this notice.
If you have any questions or concerns, please contact Hamilton City Council directly on 07 838 6699.
Further updates will be shared on this page and on our social media channels as they come available.
Boil tap water before using it for drinking, cooking or preparing food and brushing teeth.
Continue normal handwashing with soap and water. Practice good hygiene – E. coli can spread from person to person. Be especially careful around infants, older adults, and people with weakened immune systems.
Yes. Always use boiled or bottled water when preparing formula. Boil water and allow it to cool before mixing with formula. Continue breastfeeding as usual. Remember to sterilise bottles and teats by boiling or microwaving.
If washing dishes by hand, use boiled or bottled water. If you’re using a dishwasher, run it on the hot and sanitise cycle.
Bathing in tap water is ok for older children and adults but not for babies or kids who might swallow the water. Avoid the face.
If you have recent surgical wounds or a chronic illness, you may want to use bottled or boiled water for bathing until the advisory is lifted.
The boil water notice will remain in place until at least Tuesday 7 October, as three consecutive days of clear test results are needed before it can be lifted.
We’re actively investigating and running additional tests to identify the cause.
As a precaution, the Rototuna Drinking Water Reservoir has been isolated from the network, and residents are now supplied directly from our bulk water system. Residents still need to boil their water while additional sampling is carried out across the network.
No, the Rototuna Drinking Water Reservoir has been isolated from the network, and residents are now supplied directly from our bulk water system. Residents still need to boil their water while additional sampling is carried out across the network.
We expect more test results on Sunday 5 October.
There are many types of E. coli — most are harmless and naturally found in humans and animals.
The routine E. coli test we use doesn’t identify strains. Instead, it simply detects whether any E. coli are present. Their presence indicates possible contamination and signals that other pathogens could be in the water. In other words, E. coli testing is an early warning system that helps us take action quickly to protect public health.
After receiving the confirmed test result this morning, Council immediately activated an Incident Management Team at 10:45 am. We developed an operational response plan, identified likely impact areas, and notified Taumata Arowai, the Ministry of Health, and other key agencies.
Issuing a Boil Water Notice is a significant public health action. It requires coordination across multiple organisations and careful review to ensure the information is accurate. Communications began rolling out across multiple channels from 4:30 pm once all requirements were met.
Unlikely. Our water supply is tested daily at our reservoirs, treatment plant, and throughout the network. This morning’s result was the first positive E. coli detection we’ve had. Given the timing of symptom development and the low level of bacteria detected, it’s not expected to be the cause of recent illnesses. If you have health concerns, contact Healthline on 0800 611 116 for free advice.
No. Hamilton’s water supply meets all regulatory standards and has long been fully compliant with testing, monitoring, and treatment requirements.
This result was from a single test, and the cause is still being investigated. We can confirm that no essential maintenance or water quality protection work has been delayed or cancelled due to other projects.
Yes. We’re working directly with retirement villages, rest homes, and other agencies to ensure vulnerable residents are informed.
Despite our best efforts, we may not reach everyone immediately. Please help us spread the word by checking on neighbours, friends, and family in the affected area.
We’re using multiple channels to share information as quickly and widely as possible. Social media helps us reach people instantly, but we’re also:
As the situation evolves, we’ll continue expanding how we share updates. Despite our best efforts, we may not reach everyone immediately. Please help us spread the word by checking on neighbours, friends, and family in the affected area.
The impacted area starts at the Gordonton Road / Greenhill Road intersection and extends to Woodlands Estate on Whitikahu Road.
Affected roads include: