Councillor Glenn Taylor asked at Orange City Council's meeting on Tuesday night whether the water could be investigated, given the severity of the drought.

Cr Taylor said water was pumped from beneath the Phoenix Hill mine during the 1980s drought, which ran into Summer Hill Creek and then Suma Park Dam.

"Over the years, there's been conjecture about the amount of arsenic in the water and the mines and so forth, well I tell you what, Orange would have been poisoned, the amount of water pumped back into Suma Park [and it wasn't]," he said.

Technical services director Ian Greenham said it would be good to rule it in or out and treatment facilities were capable of taking out most impurities.

"I'm not aware of any trace of arsenic within Suma Park Dam itself so if it has been pumped in there in the past, there's certainly no trace of it now," he said.

Cr Taylor also asked the council to investigate dredging Suma Park while the water levels were low, to remove silt from the reservoir and increase its capacity.

"Any farmer knows during dry periods, that's what you do," he said.

"If we can improve our water storage capacity while our dams are down, why wouldn't we do it?"

Mr Greenham said it was still a large body of water, but the outer reaches could be looked at.

"We may be able to partner with one of the commercial [businesses] producing top soil," he said.

The council last week decided not to apply level five water restrictions until storage hits 30 per cent because residents were using only 145 litres per person per day.

The level five requirement is 160 litres.

Storage is currently sitting at 34.6 per cent and is projected to reach 30 per cent by October assuming no inflows.

Mr Greenham told the council on Tuesday night the Blackmans Swamp Creek stormwater harvesting scheme pumps had been turned on for two days during last week's rain and he expected them to be turned on again this weekend.

After advice from auditors, the council has stopped watering the Northcourt, Robertson Park and the cemetery, while gardens are being watered via a drip system for half an hour a week.

Wade Park is the only sports ground being watered in order to establish grass for winter sport, while Sir Jack Brabham Park is being watered occasionally.