So-called ‘flushable’ wet wipes don’t break down like paper in our wastewater network. They cause blockages, overflows and damage which costs ratepayers and risks impacts on our environmental. Used wet wipes should be binned, not flushed.
Council delivers education campaigns to help the community understand what should and shouldn’t go from their toilets to our wastewater plant.
The issue
- Hamiltonians are risking clogged pipes, environmental damage, blockages in the city’s wastewater network and public health risks every time they flush wet wipes away.
- Anything wrongly flushed into the network can cause problems, but the single worst issue, by scale and impact, is wet wipes.
- Many of the so-called ‘flushable’ wipes contain plastic fibre which can clog up pipes and pumps fundamental to the operation of our wastewater treatment plant and network.
- Overflows damage the environment. Council’s efforts to repair, mitigate and respond to blockages caused by the wrong things being flushed is additional expense for ratepayers.
- Around the world, damage caused by flushing wet wipes into the wastewater network costs network operators millions of dollars every year.
- The current impacts and future risks are so great that governments are acting. Just last month the UK introduced draft legislation banning wet wipes containing plastic, with fines of the equivalent of NZ$460 for retailers selling the products.
- But research shows even non-plastic wet wipes, claimed as ‘biodegradable’ by manufacturers, can last up to 15 weeks in the environment, where they can act as a reservoir for faecal bacteria and E. coli. Other studies have highlighted non-plastic textiles lasting for two months or more in rivers and oceans, where they break up into hundreds of thousands of microfibres.
What is Council doing?
- Council has a multi-pronged approach to keeping the network operating smoothly including public education, preventative equipment, regular maintenance, upgrades, and emergency responses.
- For almost a decade the city has been running a ‘Bin it, don’t flush it’ campaign with letter drops in suburbs, advertising, social media posts and displays at public events.
- Our Pukete Wastewater Treatment Plant is essentially a giant living organism that treats the city’s wastewater before it is returned to the Waikato River. The city’s Trade Waste team works with businesses to ensure chemical and other commercial wastewater is managed properly and doesn’t impact the biological processes at the treatment plant.
- Screening systems and barriers to contamination capture around a tonne of non-biodegradable matter which is removed from the treatment plant each day and trucked to landfill.
- Alarm systems and monitoring is part of Hamilton’s hundreds of kilometres of wastewater pipes and more than 140 pump stations.
- Special macerating pumps have been installed which are able to ‘chop up’ some congealed masses within the network, allowing flows to continue and reducing the risk of blockages and overflows.
- Emergency storage tanks have been placed in priority areas to capture overflowing wastewater in the event of power outages. These provide several hours of capacity to allow repair teams to identify and resolve issues or to install other mitigation such as vacuum trucks while the outage is resolved and before wastewater escapes into the environment. Within just a few weeks of underground emergency storage being installed in River Road last year an outage at a pump station saw the tanks in use, preventing environmental impacts.
- We have a Trade Waste team which works with businesses and others throughout the city to ensure compliance with the Trade Waste and Wastewater Bylaw. The Bylaw prohibits anyone placing any substance into the wastewater network which could interfere with its operation.
Responding to wastewater overflows is a priority for the health of our city
In 2023/24 there were 142 dry weather wastewater overflows. The majority of overflows were caused by blockages from materials such as fats and wet wipes, with a small number of overflows from wastewater pump stations due to unplanned power outage and blockages.
Weird stuff in the system
- Our dedicated staff at our Pukete wastewater treatment plant have had to cope with some odd things in the wastewater network.
- Childrens’ toys, clothing and false teeth are just a few of the unexpected arrivals at the plant, but staff have also encountered a large plank of wood (which must have been pushed down an access cover), and a dead possum. Seasonal increases in cooking fats around Christmas are another regular problem.
- Council’s plea is simple – if it’s not pee, poo or paper, don’t flush it.
- Some everyday items that should not enter the wastewater system include wet wipes, nappies, sanitary items, cotton buds, oils and grease, cleaning products/chemicals/paints, food scraps, paper, plastics and paint rinse water.
Flushed wet wipes clogging one of our screens at the treatment plant. Wipes don’t break down like toilet paper and cause blockages, equipment damage and environmental impacts from overflows. Bin them, don’t flush them, for everyone’s sake.
Further information
Feedback
Last updated 29 August 2025