These 4 Des Moines metro suburbs have grown so much they need a special census

Officials in some metro cities are betting that there's been enough growth since the last U.S. Census only three years ago to not only justify requesting a special census but also that there will be a quick return on investment to put toward local projects.

The agendas for city council meetings this week included requests for special censuses — in June 2024 in Waukee and April 2025 in Grimes. To the east, council members in Pleasant Hill also approved a special census to be conducted some time in 2024, and Altoona will have a special census in 2025.

Special censuses are not new requests in the metro: Ankeny, Clive and West Des Moines have asked for them in the past. Waukee also did a special census in 2015 that showed 30% growth since the 2010 census.

Cities are allowed to have one special federal census per decade to potentially raise their population count and receive more dollars from the Road Use Tax, which is accumulated by the state from sources including the proceeds of vehicle registrations, fuel tax, license fees and taxes on car rentals.

The money is then credited to different road funds, and from there it's allocated to local authorities — for cities, by population as shown by the latest federal census.

How much did the suburbs grow?

The U.S. Census is conducted every 10 years, most recently in 2020. The city of Des Moines' population grew more than 5.3% between 2010 and 2020, while the nearby suburbs saw even faster population growth in the decade as residents flock to new housing developments.

More: Des Moines again tops the charts for growth among large Midwestern metros, census shows

Grimes grew 87% between 2010 and 2020 — to 15,392 people from 8,246.

Waukee grew 74%, to 23,940 people from 13,790.

Altoona grew 34.6%, to 19,565 people from 14,541.

And Pleasant Hill grew 15.5%, to 10,147 people from 8,785.

Why does Waukee want a special census?

Waukee would pay an estimated $679,275 to the U.S. Census Bureau for its special census.

Waukee officials expect the city would see a return on investment in less than a year, according to City Council documents. The city would receive $128.50 in new Road Use Tax revenue from the state for every new resident who wasn't counted in the 2020 census.

That means Waukee expects to have added more than 5,000 new residents by the time the count is done.

Why does Grimes want a special census?

Grimes would pay an estimated $490,125 for its special census.

City staff in Grimes anticipate the population there has increased by 3,724 people since 2020, which would mean $446,880 in new Road Use Tax money each year, starting in 2026.

Pleasant Hill needs relate to housing boom

The western suburbs are not alone in requesting special censuses.

Pleasant Hill is requesting a special census in the 2024 calendar year given the more than 630 new housing units added to the tax rolls since 2020. Assuming an average of 2.67 residents per unit, that could mean nearly 1,700 residents who were not counted in the 2020 Census, according to city documents.

The estimated cost of the special census in Pleasant Hill is about $390,000, plus office space and incidentals.

Pleasant Hill officials estimate that the city would receive an extra $130 per new person in road tax funds and $90 per person in local option sales tax funds, which can be used for property tax relief and city improvements. That would be an annual $220 per person.

More: Use this interactive map to see what the 2020 census data says about your Iowa neighborhood

If 1,000 new people are counted in the Pleasant Hill special census, that would mean a return of $220,000 a year, and hit more than the census cost in two years. If 800 new people are counted, that would be an additional $176,000 a year, and reach the cost of the census in three years.

Altoona expects to record at least 3,500 new residents

The Altoona City Council approved plans for a special census in June 2025.

City officials expect to capture at least 3,500 new residents in the census, which would cost $565,000, and recover the costs of the census with new Road Use Tax funding after about 18 months, according to a news release.

"We’ve seen continued growth in our community, especially since the 2020 census," Altoona City Administrator Randy Pierce said in a statement. "By conducting a special census, not only will we have a more accurate representation of the population of our community, but it also opens up the opportunity to collect more funding, allowing our city to keep up with projects to benefit residents and our rapidly growing community."

Phillip Sitter covers suburban growth and development for the Des Moines Register. Phillip can be reached via email at psitter@gannett.com. He is on Twitter @pslifeisabeauty.

Chris Higgins covers the eastern suburbs for the Register. Reach him at chiggins@registermedia.com or 515-423-5146 and follow him on Twitter @chris_higgins_.

This article originally appeared on Des Moines Register: Waukee, Grimes, Pleasant Hill and Altoona want special census