Jim Holmes, from Regina Water Watch, continues to collect names for a petition on the city's new wastewaster plant. (CBC)

Regina Water Watch, the group pushing for a referendum on the city's new wastewater treatment plant, may have enough signatures to require a referendum, although they are still collecting names.

The group learned Tuesday that the province will not change the threshold needed to force a vote, as had been requested by officials at city hall.

According to the rules, the group needs 19,310 valid signatures to ensure a referendum. That is based on census data. The City of Regina wanted a higher threshold based on the number of health card holders, but the provincial minister refused to change the number.

Even though the threshold question is settled, petition organizers are still collecting names just in case some signatures are rejected.

"We want to make sure that we have a buffer," Jim Holmes, a spokesman for Regina Water Watch said Tuesday. "We think we owe that to the people that have already signed that we do everything we can to make sure that the whole petition doesn't get thrown out."

The deadline for submitting the petition is Thursday.

That is followed by a verification process.

The Water Watch group wants citizens to have a say in how Regina's new waste water treatment facility is built, financed and operated.

The city wants to involve the private sector in what is known as a P3 model.

Civic officials say that approach will save money. The Water Watch group disputes that and argues public infrastructure should be publicly managed.