Water supply

Council provides a supply of safe fluoridated water that complies with the Drinking Water Standards of New Zealand to meet the various needs of water users in the city – residential, industrial, commercial and institutional.

Palmerston North water supply

The primary water supply for the city is taken from the catchment area of the Turitea Stream at the northern end of the Tararua ranges. Water is also supplied from four artesian wells to the city’s network.

A single artesian well supplies a separate system at Ashhurst.

The Council supplies some 10.8 million cubic meters per year to Palmerston North and Ashhurst, which amounts to an average of 29,660 cubic meters per day and the average per head of population amounts to 423 per day.  This figure includes industrial use, garden hosing, hydrant flushing, fire fighting and any system losses.

Council has adopted a new Water Supply Bylaw as at 1 July 2008 see attachments below for a copy

Water quality

Although the water from the Turitea catchment is of good chemical quality its direct use is undesirable. This is common in natural run-off from bush catchments as the water is slightly coloured, periodically contains large numbers of algal cells, and after heavy rain may contain silt and protozoans such as Giardia and Cryptosporidium. The Treatment Plant (originally constructed in 1953) is provided primarily to remove the colour, as well as any algae and silt, and also to ensure the water is free of bacteria and protozoans, ongoing monitoring indicates that the treatment plant provides an effective barrier to these issues.

The quality of the artesian supplies is excellent, with the only treatment required being chlorination to neutralise hydrogen sulphide that is present naturally, and to provide residual disinfectant protection in the reticulation. These are deep bores between 300 mm and 450 mm diameter and are up to 250 metres deep.

Fluoride is added at Turitea and the four artesian stations. The level of fluoride in the water is maintained at between 0.7 and one part per million.

The Council’s laboratory maintains a close check on the water quality from all five sources. Bacteriological and general chemical quality is regularly tested and samples are collected daily in different parts of the City for analysis microbiological quality.

Turitea water source

The primary water supply for Palmerston North is taken from the catchment area of the Turitea Stream at the northern end of the Tararua Ranges. The catchment has an area of approximately 2,400 hectares which is largely covered in bush. The average rainfall is 1,400 mm per year.

This area is run under the Turitea Reserve Management Plan, this has recently been updated to include an extra purpose to the reserve so the development of a windfarm can go ahead.

A reservoir has been formed at the lower end of the catchment by constructing a dam across the stream valley. The storage capacity of the dam is 1.7 million cubic metres which meets the City’s average daily use for about 70 days.

For more detailed information (explaining the history and the technology) of the Turitea Water Supply you can view the following documents:

Turitea Water Supply

Turitea Upper and Lower Dam Specifications

Copies of this booklet are also available from the Palmerston North City Council Customer Service Centre.

Turitea Water Treatment Plant

Treatment Plant Schematic

The plant is a full conventional alum-flocculation, rapid gravity dual media (pumice and sand) filtration type. The plant can also be operated in direct filtration mode during periods of low raw water turbidity, whereby the clarification process is by-passed.

The Plant has been substantially upgraded during 1999 and is now partly automated requiring only one eight hour shift per day to ensure a continuous supply. Most of the plant functions are now automated with most of the human input being to clean and calibrate equipment as well as replenish chemical stocks. Turitea now produces water quality equal to the best conventional plants in the world with final water turbidity typically 0.02 Turbidity Units.

Artesian wells

During periods of peak demand such as meal times, the mains from Turitea are not sufficient to supply the quantity of water required. To meet this extra demand for water, four pumping stations, drawing water from artesian wells to boost mains pressure, have been constructed in the City - at Papaioea Park, Takaro Park, Keith Street and the Roberts Line area.

Additionally, 15 million litres of treated water storage is provided at Ngahere Park. This storage also helps provide the additional water for peak demand as well as emergency situations.

The pumps are automatically controlled, starting when local pressures fall below a pre-set level

These pumps provide about 40% of the City’s supply.

Hosing and water blasting restrictions

Palmerston North City, Ashhurst and Linton water supplies

When hosing & water blasting restrictions are in force they will be notified on the Public Notice page. The following restrictions then apply:

Hosing restrictions

• Garden sprinklers and hoses may NOT be used.
• Soak Hoses are strictly prohibited at all times.
• Out of day-light saving hours doesn’t change the restrictions

Water blaster restrictions

• Water blasters may be used in the allocated hours with a permit as per hosing. Outside of these hours, a permit is required.
• Permits at no charge, are obtainable from the Customer Service Centre.

To check the Water Regulations and Restrictions phone Customer Services on (06) 356 8199

Backflow prevention

Dangers of backflow

Under the New Zealand Building code water from the water network must be prevented from returning to that system. This can happen if there is backflow (a reversal of the normal direction of flow in a pipe).

This can be especially dangerous if there is also a cross connection (a connection between a drinking water supply and a source of contamination or pollution). This is a situation that can be created from something as simple as the common garden hose in a bucket to mechanical failure of appliances, machinery or valves.

There are cases where the public water supply has been contaminated with dangerous chemicals and other pollutants causing serious injury and illness because the potential for backflow was overlooked.

Prevention measures

Residential prevention measures

Householders can ensure there is no risk from operating the garden hose by fitting an inexpensive hose tap vacuum breaker available from plumber’s merchants to their outdoor hose taps.

Commercial prevention measures

Commercial buildings that have potential hazards are required to have adequate backflow prevention.

This includes:

• Hospitals and medical centres
• Agricultural and horticultural operations
• Points where portable water tankers are filled
• Premises with boilers and cooling towers.
• Some food preparation premises
• Many other situations

Council’s Water Technical Officer can assess the potential hazard of any system. For advice call 06 356 8199.

Tips on how to save water

43% of household water consumption is in the bathroom

• Take shorter showers
• If you must bath, don’t overfill it
• Turn off the tap while brushing teeth
• Check your cistern, taps pipes for leaks and overflow
• Install a dual-flush toilet cistern
• Or place a brick in the cistern, or adjust the float valve
• For further household water saving advice view our brochure "About using water wisely".

32% of household water consumption is in the garden

• Check for hosing restrictions with PNCC
• Don’t water the paths, driveways, gutters
• Use a timer and moisture metre with your sprinkler to avoid overwatering
• Only water when really necessary - not just by habit
• Water morning or evening, there is less loss by evaporation
• Deep soak plants - a few good waterings are better than lots of light sprinklings
• Use the household’s grey water
• Mulch your garden - it conserves soil water and has other benefits too
• Compost your soil - this will assist its moisture retention
• For further household water saving advice view our brochure "About using water wisely"

18% of household water consumption is in the kitchen

• Don’t run the tap when cleaning vegetables – use a bowl or put the plug in the sink
• Use your dishwasher for only full loads
• If buying a dishwasher, closely consider its water consumption
• Remember sink waste disposal units encourage more water use
• Check all taps, pipes and connections for leaks

7% of household water consumption is in the laundry

• Use you washing machine for only full loads
• Use the half water cycle if appropriate
• When looking for a new washing machine examine it’s water usage
• Check all taps, pipes, connections for leaks
• Also check your hot water supply tank and hot water cylinder breather pipe for overflowing

For further information on water conservation in the garden view our brochure entitled "Showers to Flowers"