Even though Portland voters temporarily halted the city’s plan to add fluoride to drinking water, that didn’t stop the city from spending money on the project.

Last year, the Portland Water Bureau spent $153,000 on the city’s since-halted plan, which would add fluoride to drinking water serving about 900,000 people in Portland and select suburbs. The Portland City Council unanimously approved the plan Sept. 12 but opponents immediately began collecting signatures to block the decision and force a public vote.

The Auditor’s Office on Nov. 8 certified that enough signatures had been collected, meaning the city could no longer spend money on the fluoride effort.

But already, according to city documents, spending had begun.

On Oct. 1, former Commissioner Randy Leonard proposed and won council approval to set aside $1 million from the Water Bureau’s contingency budget for fluoride. The total project cost was estimated at up to $5 million, with more money to come in the following year’s budget.

“In the event that the referral effort is successful in gathering the required 19,858 valid signatures to be placed on the ballot this request will … not be needed,” according to budget documents.

But some of the money was spent “prior to the certification of the measure,” the Water Bureau now reports.

“Already spent were $50,000 in personnel services and $103,000 in consultant services for the land use review application and initial design,” according to budget documents. Now the Water Bureau is preparing to put the remaining $800,000 back into the contingency fund — although they may tap into it later, depending on the election outcome.

Voters will decide May 21 whether to approve or reject the fluoride proposal.