Des Moines is surveying residents to determine whether there is support for a 1-cent sales tax increase.

It's a first step that could lead to a Polk County-wide vote on the issue as soon as March 2018.

Des Moines has hired lobbying firm Carney & Appleby to find out whether residents would support the increase and, if approved, how they would like to see the money spent.

The phone survey will cost the city $62,000.

"In most sophisticated campaigns ... you want to know what the voters think," Des Moines Councilman Chris Coleman said.

The Register requested a copy of the survey, but the city said it was not finalized. Results are expected in November.

Des Moines stands to generate an extra $37 million per year through a 1-cent tax increase, according to city officials. But in order to pass, it would need to win approval in the suburbs as well as the capital city.

Ninety-three of Iowa's 99 counties have a local option sales tax in place. Polk and Dallas counties are two of the outliers.

State law makes passing a local option sales tax difficult in metropolitan areas. Iowa Code calls for contiguous cities — those whose borders touch like Des Moines and its neighbors — to vote together.

In order for one city to enact a sales tax increase, the issue must be approved by voters across the metro area.

Local leaders have lobbied lawmakers for years to change the law, allowing individual cities to pass their own sales tax bumps. But that proposal has fallen on deaf ears at the statehouse.

Polk County officials backing the sales tax plan will keep their eyes on Dallas County this fall. Voters there will decide the fate of a 1-cent sales tax increase during the Nov. 7 general election.

"I believe that if the ballot passes in Dallas County in November, that clearly could be viewed as momentum for the rest of the region. There's just no question about it," Des Moines Councilwoman Christine Hensley said.

Des Moines City Manager Scott Sanders called the sales tax a "game-changer" that could be used for infrastructure improvements, enhancing neighborhood public safety or other neighborhood projects. Hensley said it could provide an alternative revenue stream to prop up public transportation, which is struggling to find alternate funding sources.

"It is important that we do have alternative revenue because we can’t be completely dependent on property tax when we don’t have a lot of property that pays it," Hensley said.

In Des Moines, about 38 percent of the property is tax-exempt. That includes things like government buildings, churches, hospital and nonprofit groups.

The city approved a 12-cent property tax increase in March, the first time it had raised taxes in five years. That allowed the city to add 16 new positions, after cutting more than 300 jobs in the previous 12 years.

Two cities in Polk County have had local option sales tax in place since the late 1980s: Polk City and Sheldahl. The tax brought in more than $3 million for Polk City in 2016 and about $138,000 for Sheldahl.

In 2006, Dallas, Polk and Warren counties tried to get the local option sales tax on ballots at the same time. The effort was dubbed "Project Destiny." It "was a disaster, in all honesty," Hensley said.

Ten Warren County communities approved a 1-cent sales tax boost in 2015.

Now that much of Warren County has approved the tax and Dallas County is pursuing it, the "stage is set differently" for Des Moines and Polk County, Hensley said.

Potential revenue

A 1-cent local option sales tax could generate an estimated $79 million annually, according to the Iowa Department of Revenue.

The agency has provided rough estimates for potential revenue, based on tax receipts from fiscal year 2016: