10,000 customers lost electricity in Melbourne's CBD on the evening of Monday, May 25, after a burst water main flooded a basement zone substation beneath a Little Collins Street car park. The flood sent thousands of litres of water into the substation at 32-60 Little Collins Street, forcing Citipower to de-energise the site and cut supply while crews pumped out water and checked equipment. The outage knocked out traffic lights, moved hospital corridors onto emergency lighting and disrupted commuter rail while crews and emergency services managed intersections. By Tuesday morning Citipower said all outages had been fixed after energy was rerouted from other parts of the network.

If you were in or near Melbourne's CBD on the evening of Monday, May 25, you may have suddenly found yourself without lights, stuck at an intersection, or watching hospital corridors run on emergency lighting.

What happened under Little Collins Street

The problem began when a water main burst and sent thousands of litres into the public car park at 32-60 Little Collins Street. Floodwater reached a zone substation in the building basement, and Citipower said crews de-energised the site for safety, initially cutting power to about 10,000 customers in south-eastern parts of the CBD.

Citipower deployed pump trucks and began removing water from the substation through the night. "Pump trucks are on site and are removing thousands of litres of water from the zone substation on Little Collins Street," a Citipower spokesperson said. Teams then moved to inspect equipment and plan specialist testing before any attempt to return the substation to service.

Because the zone substation was isolated, parts of the local grid had to operate differently while operators rerouted supply from other parts of the network. Citipower warned customers that the local network could carry higher-than-usual demand and asked affected households and businesses to minimise electricity use where possible while crews worked.

How the outage hit the city

That said, vicTraffic reported that roughly 40 sets of traffic lights across the CBD, East Melbourne and South Yarra were out, and advised road users to treat intersections without working lights the same as those with stop or give way signs.

Commuter rail services and local traffic were disrupted while crews and emergency personnel managed intersections to keep traffic moving and reduce risk.

Mastheads

Hospitals were affected but remained on contingency plans. The Epworth Freemasons facilities on Albert Street and Victoria Parade switched to emergency lighting and enacted their contingency arrangements, and staff confirmed no patients had to be moved. Epworth said patients remained safe and in care while the operator and emergency services responded.

Thing is, as the night progressed the scale of the outage reduced. Citipower updates showed that by about 8.00 pm on Monday roughly 1,000 customers were still without power in parts of the CBD.

By Tuesday morning Citipower spokeswoman Emma Tyner reported that all outages had been fixed by rerouting energy from other parts of the network. Tyner said crews expected pumping to be complete in the morning, which would let technicians safely test equipment and carry out any repairs needed to return the Little Collins Street zone substation to service.

On-the-ground work followed a two-step pattern. First, crews focused on water removal and safety checks so technicians could access the site. Second, engineers planned specialist testing of electrical equipment before any reconnection. That approach is standard when floodwater reaches electrical infrastructure because water can hide damage to insulation, switchgear and control systems.

Citipower and other operators handled customer communications through live updates. The company asked customers to follow its notices while crews worked through the night and into the morning to restore full service.

But if you lost power or are checking on someone who relies on electricity, network operators offer live tools and safety guidance. Ausgrid and other distributors maintain live outage maps and SMS alert services where customers can check current outages, estimated restoration times and report faults. AusNet runs an Outage Tracker and specifically provides instructions for people who rely on life support equipment about registration and outage alerts. Energex offers an Outage Finder map and text lists to see scheduled maintenance and unexpected outages.

If your supply is off but your address isn't showing on a distributor's outage map, report the fault through their online form or emergency number so the issue can be investigated. If you rely on life support equipment, check your registration and alert settings with your distributor so you receive direct notices in an outage.

When you come across an intersection with failed traffic lights, follow VicTraffic guidance: treat it the same as an intersection with stop or give way signs and proceed only when it's safe. If you remain without power after an operator has reported restoration, report the problem through your distributor's fault-reporting tool so crews can track and resolve any lingering issues.

Citipower, emergency services and hospital teams coordinated through Monday night and into Tuesday morning to prioritise safety while engineers assessed the substation. The immediate focus was to get water out, confirm electrical safety and then test and repair equipment before full reconnection.

The incident is a reminder of how quickly a burst water main can cascade into broader urban disruption when it reaches critical infrastructure. For now the priority has been protecting people and ensuring hospitals and emergency services could continue operating while the network was stabilised.

Related Articles

Citipower said pumping should be finished in the morning, after which technicians will test and repair equipment so the Little Collins Street zone substation can be returned to service. Originally reported by ABC News.

This article was created with AI assistance.