For the second May running, it looks like Portland's on its way to a controversy-laden vote over the city's water system.

Portland election officials expect to know by the end of the week—possibly tomorrow— whether an initiative to snatch the city's water, sewer and environmental services bureaus away from city hall will make the ballot. But based on an initial inspection of over 50,000 signatures submitted by the Portland Public Water District campaign last month, the measure stands an excellent chance.

"I thought this looked like a pretty clean petition, in particular because of the number of signatures they have," says Deborah Scroggin, election officer for the City of Portland.

In an examination of more than 6,000 signature sheets submitted by the campaign, the auditor's office rejected less than 1,500 1,725 signatures for not complying with administrative rules set by the Oregon Secretary of State's Office, Scroggin said. That amounts to about 3 percent of the estimated 50,213 signatures submitted on January 21. The measure needs 29,786 valid signature to make the May primary ballot.

There isn't really an average percentage of rejections for initiative petitions, Scroggin said, but she offered past figures for context. A 2012 effort that led to Portland's contentious fluoride vote last May had "a little less than 3 percent" of its signatures rejected by the auditor's office. The water measure campaign turned in thousands more signatures than anti-fluoride activists behind that petition.

By contrast, a 2007 petition involving marijuana regulation had a 14 percent rejection rate. It didn't make the ballot.

But the auditor's office scrutiny is only one step in the verification process. On Friday, Scroggin sent the petition's remaining 48,725 signatures to the Multnomah County Elections Office, which is sampling 10 percent to determine if the petition is valid. County elections spokesman Eric Sample expects to have conclusive findings tomorrow.

The proposed water district would take control of the Portland Water Bureau and Bureau of Environmental Services away from the Portland City Council. Instead, a seven-member elected board would make decisions on rates, infrastructure improvements and environmental services controlled by the bureaus. There are still big questions about how the arrangement would play out.

The campaign's signature-gathering effort has been controversial. A chorus of complaints rolled into the Secretary of State's Office late last year—many from foes of the effort—alleging petitioners were telling lies and half-truths to convince people to sign. Secretary of State spokesman Tony Green said the office is still investigating those complaints.