Christchurch City Council is considering charging households that use excess water in a bid to make the service fairer and ease pressure on the system during peak demand over summer.
The idea will be be put forward for public feedback under the council’s draft Annual Plan.
It would apply to households that use more than a third more water than the average household and work in the same way as water charges already in place for commercial properties, said city council head of three waters and waste Helen Beaumont.
"Households that use much more water than the residential average put extra demand on the city’s water supply network, including the wells, pumps and pipes we use to deliver water to those households.
"The average daily household water use in Christchurch is equivalent to about seven baths per day, whereas the top 20 per cent of households use at least 11 baths per day, and some significantly more.
"To put it another way, the top 20 per cent of households use half of the total residential water supplied to the city.
“We’re proposing that where a property owner uses significantly more water than the average household, they contribute to the cost of supplying that extra water.”
Currently residential property owners pay for an allocated water supply using a targeted rate based on the rateable value of their property.
Commercial users also pay a targeted rate, but then pay an additional water charge - at a rate of $1.05 per 1000 litres - if they exceed their allocation covered by their rates.
The council’s proposed excess water charge would apply to those households that use more than 333,000 litres per year (915 litres per day) and exceed their rates-based allocation.
Usage would be assessed and charged for on a quarterly basis, with a credit applying if a household’s use was below allocation for a quarter.
In Christchurch, the average annual household water use is 197,100 litres - the highest of all the larger cities in New Zealand.
The council estimates the proposed charges would initially affect about 20,000 households and bring in an additional $2 million in revenue in the first year. Over time, fewer properties could be affected if high-use households reduce their water use.
“Ultimately, it’s about making the service fairer while also helping to reduce the peak demand we see every summer and the need for water restrictions,” Beaumont said.
“Currently there’s no good way to manage that high-use demand, apart from imposing blanket restrictions across the city as a last resort, and that has a negative impact on everybody, including the low and ordinary water users who make up the majority.”
Summertime household water consumption in Christchurch is about double that in winter, mostly due to people watering lawns and gardens with sprinklers and irrigation systems.
Last summer the city recorded its highest single-day water use in a decade – an average of 1324 litres per household.
