Published 4/02/2017
Chlorination of Lower Hutt's water supply
People in Lower Hutt who normally receive unchlorinated drinking water may notice a slight smell and taste of chlorine in their water from this evening.
As part of the routine water testing carried out on the Lower Hutt network, a sample from the Naenae reservoir has returned a positive e-coli result.
E-coli is an indicator for contamination. At this stage there is no way of knowing whether the water is contaminated or not. So as a precaution, Wellington Water staff are adding chlorine to the reservoir and at distribution points below the reservoir.
For extra security, chlorine is also being added at the treatment plant that supplies normally unchlorinated aquifer water to the majority of Lower Hutt residents (except Wainuiomata, Stokes Valley and Manor Park - these areas are already chlorinated).
Wellington Water advises that water already in pipes should be treated as safe to drink. There is no need to boil water.
The public artesian wells at Buick Street in Petone, and Dowse Square in central Lower Hutt remain open as a source of unchlorinated drinking water.
Wellington Water will carry out tests on multiple samples at other reservoirs and points in the water network, and provide updates to Lower Hutt residents as soon as more test results come in.
Additional information:
1. Wellington Water delivers around 140 million litres of safe drinking water to the people of metropolitan Wellington every day.
2. We have a rigorous and thorough testing programme to ensure water is safe to drink.
3. Metropolitan Wellington’s water comes from a secure aquifer, rivers, and, in times of shortage, storage lakes.
4. Water from the rivers and lakes is chlorinated before delivery. Water from the aquifer usually isn’t chlorinated.
5. About 76,000 customers in the Lower Hutt receive unchlorinated water supply. From time to time, we need to chlorinate some or all of this supply as a precaution against contamination.
6. The Waiwhetu aquifer and our extraction points and processes are subject to regular testing and checks to ensure water quality. All testing complies with or exceeds the Drinking Water Standards of NZ.
7. From time to time, a test will return a positive e-coli result. This does not necessarily mean the water is contaminated. As a precaution, we will always introduce chlorine to part or all of the network after a positive result, until re-tests confirm there is no risk of contamination.
8. Chlorination is one barrier to contamination. Other barriers are regular testing, and storage buffers. Having water stored in reservoirs means we have the opportunity to test and chlorinate water before it reaches customers.
9. Many customers accustomed to a non-chlorinated supply will notice the addition of chlorine to their drinking water.
10. The addition of chlorine to the water as a precaution against contamination does not mean the water needs to be boiled before drinking it.