The mysterious humming noise keeping Sydneysiders up at night

The faint rustling of garbage bags is the only noise Sarah Grafton should have heard when she took out the rubbish on an ordinary Tuesday night. But then came the cacophony of rapidly whooshing water and loud humming sounds that rang out in the air.

Grafton has lived in North Parramatta for more than 30 years, and said she had never heard anything like it before.

“It sounded like an absolute torrent of water, with a little bit of a piercing, whooshing sound. It felt like the noise was in the atmosphere, it felt like it was close – not underground or inside a house,” she said.

The sound proved incessant – it droned on even after Grafton walked up and down her street to stretch her legs, and was also there when she woke early in the morning.

Grafton’s experience was far from a one-off incident. Since the end of August, many disgruntled residents have lodged similar complaints about the noise in Rydalmere and Ermington with the City of Parramatta and the NSW Environment Protection Authority.

All complaints have similarly described the noise as a constant low hum, occurring primarily between 6pm and 6am, according to the EPA.

Metro West tunnelling, development on sites in Melrose Park, and late-night drone activity by NSW Police were initial suspects of the sound before they were ruled out by the council and the EPA.

The source of the humming has since been narrowed down to three businesses in the Camellia industrial area.

On Monday, between 8pm and midnight, EPA and council officers conducted a noise survey at Rydalmere Wharf and three residential streets in Rydalmere and Ermington, where they detected sounds matching the reported humming.

“We acknowledge that noise pollution can be both frustrating and disruptive and want to thank the community for their patience as we have worked to identify the noise’s source,” an EPA spokesperson said.

“We are continuing the investigation and will work with all three premises to further pinpoint the sources of the noise, with the aim of mitigating the issue and reducing noise impacts on the surrounding community.”

All three premises are regulated by the EPA, and the council will assist the investigation before further action is taken.

City of Parramatta spokesperson said: “The health and wellbeing of our residents is our highest priority.”

The Sydney Morning Herald has opened a bureau in the heart of Parramatta. Email parramatta@smh.com.au with news tips.