DES MOINES — Iowa’s aging prison system is 21 percent over capacity and officials warn that any meaningful solution could take years because of the huge cost.

As of Thursday, there were 8,813 inmates in the state’s prisons, which are designed to hold 7,256 inmates.

The problem is even more evident by looking at the individual prisons.

The Anamosa prison is designed to hold 913 inmates, but on Thursday there were 1,276, corrections department records show.

There were 967 inmates at the Mount Pleasant Correctional Facility, which has a capacity of 775, and in Fort Madison, there were 573 inmates, 24 over capacity.

State Sen. Gene Fraise, D-Fort Madison, said he will push to start plans to upgrade the prisons.

“There’s a lot of design and planning,” said Fraise, who will chair a legislative study committee on the issue. “It’s going to take a minimum of five years.”

At the top of the priority list is the women’s prison at Mitchellville, where overcrowding is among the worst in the state — its 620 inmate population is nearly 200 over capacity — and the prison at Fort Madison, parts of which date to 1839.

The Iowa Department of Corrections hired the Durrant Group, a Dubuque-based consulting firm, to study the state’s prison system.

The study found that adding 320 spots for women inmates would cost $21.6 million. Adding prison space for men could cost more than $47 million.

It also found no easy solutions to overcrowding at Fort Madison.

The study estimated the cost of building a new prison there at $105.7 million. Renovating the existing prison would cost even more — about $132.7 million.

The biggest area of concern is the projected growth in the number of female inmates.

“The number of female offenders is expected to exceed capacity by 30 percent by mid-2007,” the study said. “By mid-year 2016, the female population is expected to exceed current capacity by 72 percent.”

Corrections department spokesman Fred Scaletta said the agency’s board is studying the report but it was unclear when a recommendation would be made to the Legislature.

There’s pressure to make a recommendation because state agencies must submit proposed budgets to Gov. Chet Culver by October.

Culver spokeswoman Courtney Green said the governor is waiting for a recommendation from corrections officials before taking a position on the issue.