Across the Wellington region, there are around 30-40 instances per week when the water needs to be shut off. Most water main bursts are fixed within a couple of hours. However, a range of factors can affect how long it takes:
Where the burst is. A burst in the middle of a busy road means traffic management has to be organised. In some cases, e.g. during rush hour, repairs may be delayed until traffic volumes reduce.
How bad the burst is. A split along a pipe can take more time to dig out and fix than a local or transverse split.
Other buried services. Gas, electricity and telecoms all share underground real estate with water. Sometimes these other services are in the way, and we have to organise their people to help out.
Network issues. Often the area affected by a burst can be minimised by shutting off valves to isolate as small an area as possible. Sometimes the valves aren’t in the right place, and we can’t ‘re-route’ water to as many houses as we’d like.
System re-charging. Water is delivered under pressure. In some cases after a shutdown it can take a while for the network to recharge. Often in these cases it will take higher (altitude-wise) parts of the affected area longer to regain normal pressure than lower areas.
Auto shut-off valves. From time to time a serious burst will trigger the automatic shut-off valve at the supply reservoir. Auto shut-off valves are part of our resilience planning – they are intended to reduce the amount of water lost in the event of a sudden major burst, as might happen in an earthquake. This can affect supply or pressure to a much larger area than that affected by the burst itself. Once triggered, they have to be re-set, but this generally doesn’t take too long – an hour or so.
So for these reasons it’s difficult to say exactly how long the water will be off for. But you can be assured that service staff are working as hard as they can to get the water back on as quickly as possible.
What can I do in the meantime?
Please make sure appliances that use water – washing machines, dishwashers – are switched off.
Please don’t use water from your hot water cylinder, if you have one – it could damage it.
If you can, avoid flushing the loo unless absolutely necessary.
Do you have emergency water supplies? If you’re desperate for a cup of tea or really need to use water, this could be a good time to make use of those supplies. Remember to boil any bulk-stored water before drinking it, and to replace it.
You may want to leave a tap slightly open so you know as soon as the water comes back on – but remember to leave the sink clear, and turn it off if you go out!
When the water comes back on…
It may have a milky or discoloured appearance. This is due to air in the system. It should clear after a couple of minutes of running the cold tap.
The water may also look dirty or have a brown tinge to it. This is caused by changes in water pressure which may have dislodged silt that lies in the pipes. Again, this should clear after running your cold tap for a short time.
If the water has not cleared after 15 minutes or so, please call your city council and let them know.