Police uncovered a large hydroponic set-up in a two-storey home in Dagmar Berne Street in early November last year. They found 94 plants estimated, when mature, worth over $300,000 on the street.

The discovery was the biggest for ACT Policing in more than a year.

It sparked a two-month long investigation that culminated in a raid on a Charnwood home on Wednesday morning. Police arrested three men in their 20s.

Police were first alerted to the Macgregor house by a passer-by, who noticed an unusual amount of water leaking from the home.

Inside, police discovered a hydroponics set-up on the second floor, with plants that appeared to be about two months old and roughly 1.5 metres tall.

The three men will face the ACT Magistrates Court on Thursday, where police will oppose bail. They will be charged with cultivating a traffickable quantity of cannabis for sale.

The arrests come as police continue to investigate a number of other hydroponic marijuana discoveries in recent months, none of which has been found to be linked at this stage.

Just a week after the drug house bust in Macgregor, police discovered a haul of hydroponic equipment dumped at Kaleen High School.

The collection of hydroponic bulbs, ducting and liquid fertiliser was found near bins at the school.

Police said on Wednesday that they have been unable to find any link between the dumped equipment and the Macgregor drug house bust.

Criminal Investigations detectives also discovered another large hydroponic set-up in Forde in late November.

The house, which was operating in a newly-constructed home on Proud Street, contained drugs worth $300,000.