Rotorua. Photo / Felix Desmarais
A temporary health warning has been put in place after sewage overspill flowed into the Mangakakahi Stream on Saturday.
It's prompted a reminder from the Rotorua Lakes Council not to put wet wipes, fat and rags down sinks drains and toilets.
Both incidents, in Beryl Pl and Alison St, were caused by manholes overflowing due to blockages caused by wet wipes, fat and rags.
The overflow in Beryl Pl involved a small amount of wastewater but some entered a nearby drain that flows into the Mangakakahi Stream which, in turn, flows into the Utuhina Stream.
A smaller overflow in Alison St was in a different branch of the sewage network but a small amount reached a drain that also flows into the Mangakakahi Stream.
The incident in Beryl Pl was reported by a member of the public just after 11am and contractors were finishing the clean-up when they were contacted about the overflow in Alison St.
Contractors who responded cleaned and disinfected the sites and found and cleared the blockages that caused them. Both sites will be monitored. Further water samples will be taken from the Mangakakahi and Utuhina streams.
Temporary health warnings were issued in several places to warn people against contact with the water in case of contamination.
The Bay of Plenty Regional Council, Toi Te Ora Public Health and relevant iwi representatives have been notified.
The results of the samples should be known tomorrow but sampling will continue until the all-clear can be given for the waterways, the council's infrastructure networks performance manager Eric Cawte said.
"We believe the two incidents are unrelated although they were coincidentally at around the same time and caused by the same problem," he said.
Cawte said Saturday's incidents serve as a reminder to people to understand the damage that can be done by putting the wrong things down their sinks, toilets and drains.
Wet wipes, fat and rags cause blockages in the system and can also become fatbergs - fat and other non-biodegradable solids that join to become one large mass.
Saturday's overflows followed three other incidents this year that were caused by fatbergs.
"Fatbergs and blockages caused by the likes of fat, wet wipes, rags and tissues create a back-up of sewage in the pipeline and manholes become the overflow point," Cawte said.
"[Saturday's] incidents were confined to small areas, reducing the potential public health and environmental risk, but we urge people to please remain vigilant about what they're putting down their sinks, drains and toilets."
Cawte said products that indicate they are "'flushable' can also result in significant issues for the council's wastewater infrastructure and more importantly, the environment.
"We need everybody in the community to do their bit to avoid blockages. Keeping foreign substances and objects out of our system is the best way to do that."
• Wastewater comes from your kitchen and laundry sinks and appliances, from showers, baths and toilets.
• Get rid of cleaning wipes in the rubbish bin - don't flush them.
• Let fat solidify and then dispose of it in the rubbish bin.
• Council owns and maintains approximately 500km of gravity mains, 8000 manholes and more than 20,000 homes and businesses are connected to the wastewater network.
• Items that have been found in our wastewater network include not just wet wipes and solidified fat but also children's toys, cutlery, an oil can, building materials, a hedgehog and a pig's head.