Giardia in Water
Testing and UV Filtration Solutions
Call 0800 278 296 to talk to a Water Specialist
Do you have Giardia in your drinking water?
If you rely on tank or untreated water in Rodney or rural Auckland, there is a real risk your drinking water could be contaminated with Giardia, one of the most common waterborne parasites in New Zealand (see our guide to contaminants in drinking water).
Even water that looks clean can contain Giardia, as it is invisible to the naked eye, meaning many households are exposed without even knowing it.
What is Giardia in drinking water?
Giardia is a microscopic parasite that lives in the intestines of humans and animals and can spread through contaminated water. It is commonly found in untreated water sources such as lakes, rivers, rainwater tanks, and rural supplies where contamination from animals or environmental runoff can occur.
At Aqua Works, we help identify and eliminate Giardia risks by testing your water and installing proven treatment systems to ensure safe, reliable water for your home.
If you are unsure about the safety of your water, the first step is to have it tested. Give us a call and get peace of mind.
Think you have Giardia? Do this now
1
Stop drinking untreated water
Don’t use it for drinking, cooking, making ice or brushing teeth.
2
Boil it or use bottled water
Bring water to a rolling boil for one minute, or let an electric kettle boil until it switches off. Boiling kills Giardia in the water you boil, so it’s a short-term fix.
3
If anyone is unwell
See your doctor or call Healthline free on 0800 611 116, any time. A doctor can test for Giardia and treat it.
4
Call Aqua Works
We’ll test your water, find out how contamination is getting in, fix the source and install UV treatment that stops Giardia.
Understanding the risk of Giardia in your drinking water
How does Giardia get into your water?
Giardia enters drinking water through contamination from animal and human waste. In New Zealand, this commonly happens when bird and possum droppings on roofs are washed into rainwater tanks, or when untreated surface and rural water sources are used.
Once in the system, the parasite can survive in water for long periods, increasing the risk of exposure through everyday use.
Why Giardia is a risk in Rodney & tank water
In areas like Rodney and rural Auckland, many homes rely on rainwater tanks or untreated water supplies, which are more vulnerable to contamination. Across New Zealand, waterborne diseases such as giardiasis are regularly linked to untreated drinking water and environmental exposure.
As tank water is collected from roofs, it requires proper treatment to ensure it is safe for everyday use.
When should you be concerned about Giardia in your water?
You should be concerned if your home uses tank, bore or untreated water and does not have a reliable treatment system in place. Contamination can occur without any visible warning, and symptoms may only appear after exposure.
If your water has never been professionally tested, or your system has not been checked recently, it is important to confirm that your water is safe.
What doesn’t work
Many homeowners assume their water is safe or rely on basic treatment, but Giardia is more resistant than most contaminants and requires the right system to be properly controlled.
Common approaches that don’t provide reliable protection include:
- Standard water filters that are not designed to remove parasites
- Low-level chlorination, which is less effective against Giardia
- Untreated tank or surface water
- Boiling water as a long-term solution
Giardia cysts can survive in water for extended periods and are not always removed by simple treatment methods.
For consistent, long-term protection, a properly designed treatment system is essential.
Make sure you install the right system the first time.
Health risks associated with Giardia in water
Giardia infection (giardiasis) affects the digestive system and is one of the most common illnesses caused by contaminated drinking water. The symptoms are:
Diarrhoea
Stomach cramps
Bloating and gas
Nausea and fatigue
Giardia symptoms can appear days or even weeks after exposure and may last for an extended period if the source of contamination is not addressed. Not everyone will show symptoms, but the parasite can still be present and spread within a household.
Giardia is a notifiable disease in New Zealand
The Drinking Water Standards for New Zealand 2022, regulated by Taumata Arowai, set the legal limit for Giardia and other protozoa in potable water.
Zero tolerance: there must be less than 1 infectious protozoa per 100 litres, so safe drinking water should be free from Giardia.
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Why water testing is essential
Giardia cannot be seen, tasted or smelled, which means contaminated water often appears completely normal. Without proper testing, it is impossible to know whether your water is safe or if treatment is required.
Know what you’re dealing with
Testing for Giardia itself is complex. It needs around 800 litres of water, so it’s rarely done. Instead, we test for E. coli, which shows whether faecal contamination is getting into your water. If E. coli is found, Giardia may be present too.
We use Hill Laboratories in Hamilton, an accredited lab, and can arrange three types of test:
- E. coli test: checks for E. coli only.
- Food safety test: E. coli, coliforms and turbidity (how cloudy the water is).
- Full chemical analysis: can include E. coli, plus a wide range of minerals, metals and chemicals covered by the NZ drinking water standards.
Avoid the wrong solution and start with the right advice
Different contaminants require different treatment methods. Installing the wrong system, or assuming your water is safe, can leave your household exposed to ongoing risk.
At Aqua Works, we carry out onsite water assessments to give you clear answers and recommend the right solution for your home. Testing is the first step to ensuring your water is safe, reliable, and properly treated.
How Aqua Works solves Giardia problems in your water
Giardia is highly resistant to basic treatment methods and requires a properly designed system to ensure safe drinking water. At Aqua Works, we provide whole-house treatment solutions that protect every tap in your home, not just a single outlet.
Proven disinfection systems
Our systems use technologies such as:
- UV water filtration
- Ozone tank water treatment
- Pre-filtration to ensure system performance
UV systems are widely used in water treatment because they effectively inactivate Giardia by disrupting its DNA, preventing it from reproducing or causing infection.
Designed for your water
Every system is tailored to your water source, tank setup, and household usage.
We ensure:
- Reliable protection against bacteria and parasites
- Consistent water quality at every tap
- Long-term system performance
Our process: test, design, install, service
We make it simple to ensure your water is safe, with a clear step-by-step approach tailored to your home and water supply.
1
Test
We take a water sample for testing by Hill Laboratories, an accredited lab, to check for E. coli and other contamination risks.
This ensures we understand exactly what you’re dealing with before recommending a solution.
2
Design
Based on your water source, tank setup and household usage, we design a system that provides reliable, whole-house protection.
Every system is tailored to suit your specific requirements, not a one-size-fits-all approach.
3
Install
Our experienced team installs your system professionally, ensuring it operates correctly from day one.
Systems such as UV disinfection work instantly as water flows through, neutralising harmful microorganisms.
4
Service
Ongoing servicing ensures your system continues to perform as expected.
Our annual UV service replaces the lamp, cleans the quartz sleeve, checks and replaces the filters and sterilises the lines, keeping your protection against Giardia effective.
Don’t guess, know your water is safe
Giardia requires the right treatment system to be properly controlled. Without testing, it’s impossible to know if your water is safe or if your current system is doing the job.
Giardia in water FAQs
What is Giardia in drinking water?
Giardia is a microscopic parasite found in contaminated water that can cause gastrointestinal illness when ingested. It is commonly present in lakes, rivers, and untreated water supplies in New Zealand.
How do you get Giardia from drinking water?
People become infected by swallowing contaminated water, often from rainwater tanks, untreated supplies, or surface water affected by animal waste from birds or vermin such as possums and rats.
How do you test for Giardia in water?
Giardia testing is complex and rarely done routinely. It needs around 800 litres of water, so it’s not a common water test.
Instead, water is tested for E. coli, which indicates faecal contamination. If E. coli is found, there is a high risk that Giardia may also be present. E. coli is the test the New Zealand water regulations use, because it’s easy to perform and very cost-effective. We send samples to Hill Laboratories in Hamilton, an accredited lab.
Is Giardia common in New Zealand?
Yes, Giardia is one of the most common waterborne parasites in New Zealand and is frequently linked to untreated drinking water and environmental exposure.
What are the symptoms of Giardia infection?
Common symptoms include diarrhoea, stomach cramps, nausea and fatigue. Symptoms usually appear 7–10 days after exposure and can last for several weeks.
Can boiling water remove Giardia?
Boiling kills Giardia in the water you boil: bring it to a rolling boil for one minute, or let an electric kettle boil until it switches off. But it’s only a short-term solution and not practical for everyday household use. Long-term protection needs a proper treatment system such as UV filtration.
Does a water filter remove Giardia?
Not all filters remove Giardia. Standard household filters are often ineffective unless specifically designed for parasite removal or combined with disinfection systems.
Is tank water safe to drink in New Zealand?
Tank water can be safe, but only if it is properly treated. Without treatment, it is at higher risk of contamination from animals, environmental runoff, and microorganisms like Giardia.
Does UV treatment kill Giardia?
Yes. UV disinfection is highly effective at neutralising Giardia by damaging its DNA, which stops it causing infection.
How do I know if my water has Giardia?
Giardia can’t be detected by sight, taste or smell. Because a Giardia test needs so much water, we test for E. coli instead: if E. coli is present, Giardia may be too. If you’ve had a positive result or anyone is unwell, see what to do now.
Aqua Works Guarantee
At Aqua Works, we guarantee E. coli*-free drinking water that meets New Zealand drinking water standards and all legal requirements.
Applies to rainwater and bore water with the right pre-treatment, when Aqua Works installs or services your UV system and keeps servicing it at the agreed intervals (usually every 12 months). It doesn’t cover surface water from streams, rivers, dams or lakes. We can’t take responsibility if your raw water quality changes. Recommended testing: rainwater, none needed; bore water, a full routine chemical test every two years; commercial supplies, E. coli every 3 months plus a full routine chemical test every 12 months.
*E. coli-free means no active E. coli and water that passes NZ drinking water standards.
Why Choose Aqua Works
Local experts in tank and rural water systems
We understand the real risks of Giardia in Rodney, where rainwater tanks and untreated sources are common, and we design systems specifically for these conditions.
Local water experience since 2000
We’ve been testing and treating tank, bore and spring water across Rodney and the North Shore since 2000, so we know the local conditions.
Complete solution: test, design, install and service
We don’t just install filters. We test your water, design the right system, install it properly, and service it to ensure long-term protection. Benefit from all trades under one umbrella! We make sure your water is safe, compliant, and protected.
Trusted by hundreds of local homeowners
With hundreds of positive reviews and long-term customers, we’re known for reliable service, expert advice, and results you can trust.