A triggered earthquake valve caused water outage in Westport and Carters Beach

An earthquake valve located at the Westport Water Treatment Plant was triggered yesterday afternoon at 3:04pm causing low to no water pressure in areas of Westport and Carters Beach.  

This was not due to any seismic activity, but rather a large amount of water being flushed through the 8" water trunk main as part of re-livening the connection between Stephen Road and Westport. Re-livening this part of the piped network meant flushing water through a pipe after it had been shut off.   

The re-livening was part of scheduled maintenance work. The dramatic increase of flow in the pipe triggered the valve, which was unexpected and has not occurred before when carrying out similar work.   

It meant that some consumers in Westport and Carters Beach were without water for approximately one hour. Council’s maintenance contractor, WestReef Services Ltd, was able to re-open the earthquake valve and restore system pressure. 

Mike Duff, group manager infrastructure services said: “It was great to see how swiftly, and immediately WestReef Ltd and council staff responded to the issue. This prompt and well-coordinated response enabled us to deal quickly with the outage, inform the community and key water users, and restore the water pressure as fast as possible.” 

After the earthquake valve was reset and re-opened the remainder of the pipe network was checked for damage and the water pipes were flushed to remove any remaining airlocks. 

Some people may have experienced some further interruptions during this flushing of the network. The Westport and Carters Beach water supply was fully back to normal by 5pm. 

“The team continued to monitor the system and get it back up to speed through the early evening.”   

“We have begun the debrief to understand better what caused the valve to trip. A big learning from this event is, that in the event of an earthquake this critical protection valve will function as it is intended to do.” 

Council apologizes to consumers for any inconvenience caused.   

-ENDS- 

For further information please contact: 
Group Manager Infrastructure Services  
Mike Duff 
michael.duff@bdc.govt.nz