Hunter Water is consulting with legal experts to find out if it can release the findings of an investigation into coal seam gas sewer contamination.

The authority commissioned an investigation into the release of treated flowback water from AGL's Gloucester CSG project into the sewer system last year.

The study was prompted by revelations that a contractor for AGL, Transpacific, had been discharging the treated flowback water into Hunter Water's sewers.

Hunter Water charged the company $30,000 for the breach of its trade waste agreement.

Work at AGL's Gloucester site were later shut down after the discovery of elevated levels of toxic B TEX chemicals in flowback water.

New South Wales’ Environment Protection Authority and Department of Resources and Energy are conducting investigations too.

For its study, Hunter Water requested post treatment samples of the trade waste water, to find out if it contained any toxic chemicals.

The group has now completed its analysis of that material, and is getting legal advice on whether it can share the information with third parties.