Information and advice on drinking water in the Gisborne district.
Flush water before drinking
Residents are reminded of the Ministry of Health recommendation to flush a mugful of water from drinking-water taps (including those with filters) each morning before use to remove any metals that may have dissolved from plumbing fittings.
This is recommended for all households, including those on public and private water supplies.
City water supply
Waingake water treatment plant
Gisborne city's water is supplied from 2 main water catchments, the Mangapoike dams (Williams, Clapcott and Sang) and the Te Arai Bush Catchment.
The untreated water from these sources is treated at the Waingake Water Treatment Plant, before travelling a 30km pipeline to the city's reticulation network, before being delivered to your tap.
Waipaoa water treatment plant
Gisborne also has a secondary treatment plant located at the Waipaoa River. This augmentation plant was built in answer to the wide spread devastation caused by Cyclone Bola in 1988.
This plant draws water from the Waipaoa River and is essentially only used as a 'back-up' supply during peak water demand in the height of summer and in emergency situations.
Most of Gisborne city's water comes from the Waingake Water Treatment Plant.
Is fluoride added to the water supply?
Yes, if you live in Gisborne city and receive reticulated water.
The 2 rural water supplies at Te Karaka and Whatatutu are not fluoridated.
The dosage is 0.7-1.0 milligrams per litre as recommended by Ministry of Health (MoH). Should the MoH position on fluoridation of drinking water change, we would consult with the public.
The Ministry of Health is in strong support towards water fluoridation. Council is following the Ministry’s stance as being a safe, effective and affordable way to prevent and reduce tooth decay across the whole population.
Is our water hard or soft?
Yes, if you live in the Gisborne city and receive reticulated water.
The 2 rural water supplies at Te Karaka and Whatatutu are not fluoridated.
The dosage is 0.7-1.0 milligrams per litre as recommended by Ministry of Health (MoH). Should the MoH position on fluoridation of drinking water change, we would consult with the public.
The Ministry of Health is in strong support towards water fluoridation. Council is following the Ministry’s stance as being a safe, effective and affordable way to prevent and reduce tooth decay across the whole population.
Water fluoridation is a very controversial topic.
There is an enormous amount of information available on both sides of the argument.
The effectiveness of water fluoridation has been documented in scientific literature for well over 50 years. Data from the 1930s and 1940s shows that even before fluoridation, children drinking naturally fluoridated water had lower decay rates than children consuming water without fluoride.
Studies have also shown that when communities stop fluoridation, there's a reversal of the benefits, an increase in decay rates and a large increase in the number of baby teeth extracted.
It's true that over the years, decay rates have declined in both fluoridated and non-fluoridated areas. This can largely be explained by the use of fluoride toothpaste and the cross-over effects of food and water containing products from fluoridated areas.
Most recent studies continue to show that the difference between fluoridated and non-fluoridated areas continues to be significant throughout life.
The World Health Organisation has reviewed the data available and the Public Health Commission in New Zealand published an extensive review of water fluoridation in 1994 and supports fluoridation.
In September 2000 the Ministry of Health released a report, written by Environmental Science and Research Ltd, evaluating recent evidence of the fluoridation of water supplies. This report provides further support for the safety and effectiveness of water fluoridation.
In 2003 the Public Health Advisory Committee also reviewed evidence of the effect of water fluoridation with respect to reducing inequalities in oral health. It strongly recommended increasing the proportion of the New Zealand population receiving fluoridated water.
Therefore unless there is a significant "will to change" the status quo should remain.
Gisborne District Council's reticulated water supply to city residents always complies with the Drinking-Water Standards for New Zealand 2005 (Revised 2008).
In a water emergency or if we're experiencing drought conditions and water restrictions are put in place, we'll supplement the water supply with water from the Waipaoa River.
When we do this, residents may notice a difference in taste due to the different water source, but the water is safe to drink.
The Tāirawhiti District Public Health unit acting on behalf of Ministry of Health can verify this.
The water supplied from the Waingake water catchment (Mangapoike dams) can be described as 'soft water'.
The water supplemented from the Waipaoa River to the council supplied water can be described as 'hard water'.
Soft water has less calcium and magnesium, while hard water has high calcium and magnesium.
Hard water makes it difficult to lather up soap and the minerals form a residue that makes it harder to rinse items.
This includes your hair, dishes and glassware in your dishwasher may be left with a white chalky scale or water spots.
A long-term effect is it can cause scale to develop on the inside of pipes.
If the hard water is affecting your clothes, dishes and dishwasher, or your hair feels sticky and dull, here’s some home remedies to try:
- place a small dish filled with lemon juice, vinegar or baking soda on the top rack of the dishwasher during a cycle. Another tip is 1 teaspoon of citric acid in with the detergent.
- descale your electric kettle - boil some white vinegar.
- for your hair - use a rinse of one table spoon vinegar or lemon juice to three parts water.
- some laundry detergents are better for hard water or have different instructions for how much you should use. Check the label on your powder or detergent.
- reduce the temperature of your hot water cylinder can reduce the amount of mineral build up in pipes.
Yes it's absolutely safe to drink.
Regarding public health opinions: The water is compliant with the very stringent NZ Drinking Water Standards.
Questions have also been asked about the quality of the water from the Waipaoa River.
An extensive one year (26 sample) raw water cryptosporidium testing programme was conducted on the Waipaoa River in 2010-11.
This testing was approved by the local Drinking Water Assessor acting on behalf of the Ministry of Health. The treatment processes that we apply to the water from the Waipaoa River, based on the quality of water found in the extensive sampling, complies with the drinking water standards.
There is an approved Public Health Risk Management Plan in place for each of our water treatment plants, addressing every risk aspect of the source extraction, treatment process, disinfection and delivery to the customer.
The sum of all calcium and magnesium compounds in water results in the total hardness, measured in milligrams calcium carbonate per litre (CaCO3 mg/L)
The water supplied to Gisborne from the Waingake Water Catchment has a total hardness level of below 100 mg/L of calcium carbonate CaCO3 and can be described as soft. It typically ranges between 30-70mg/L CaCO3
The Waipaoa River water is higher with a CaCO3 equivalent concentration greater than 120mg/L are considered to be hard and the combined hardness levels of the Waingake and Waipaoa treated water measured where it enters the city is generally between 100-180mg/L depending on water demand.
Water hardness is described as an "aesthetic determinand" in the Drinking-water Standards for New Zealand 2005 (Revised 2008). This means a property that can adversely affect taste, colour or general appearance of water. Guideline values (GV) are applied to aesthetics – these are levels that if exceeded, may make the water unattractive to consumers. The GV for total hardness is 200mg/L CaCO3