Who knew that dirt could stir up a debate? Right now in Iowa, however, topsoil is doing just that.

The Iowa Environmental Protection Commission, which was appointed by Gov. Terry Branstad, is considering rethinking a new rule that says that home developers and builders need to make sure that all new homes are given at least four inches of topsoil. Many builders and others have reacted negatively to the rule, saying that it will be prohibitively expensive.

The commission has agreed that it will consider replacing the requirement with rules that will ensure that homebuyers have adequate topsoil, but will not add on unnecessary costs.

The cost per home under the current rule, according to Creighton Cox, the executive officer for the Home Builders Association of Greater Des Moines, could be up to $6,000. Much of this cost is in inspections, management expenses, and extra testing. Cox says this means that thousands of families — 11,000 by his estimate — will be priced out of the market, unable to buy a new home.

On the other side are city planners and environmentalists, who worry about the potential impact of cities lacking soil. “Our soils and urban area have lost 60 to 80 percent of their ability to absorb rainfall,” says Pat Sauer, a member of the Iowa Storm Water Education Program in Ankeny. Sauer says that it’s not a choice of whether homeowners pay — it’s a question of when, and how much.

Many homes built before the four-inch requirement lacked topsoil and instead would have heavy clay sub-soils that didn’t irrigate correctly, and couldn’t easily grow plants. If a homeowner needs to add work to restore soil later, it can be much more costly compared to when the home is being built — as much as $16,000.

“In order to have a happy grass plant, you need to have a healthy topsoil base,” says Don Saunders, President of Saunders Landscape Supply. “The topsoil provides all the necessary nutrients for grass and landscaping to grow properly.”

The environmental impact of a lack of topsoil isn’t anything to sneeze at, either. When soil can’t absorb rainfall, cities are in danger of flash flooding, degraded waterways, and runoff problems. These issues can end up being much more costly than an initial $3,000 average investment. “It’s always cheaper to cut corners,” said Virginia Zoelberg, who is a member of the Iowa Chapter of the Sierra Club, but, as she points out, in the end it only leads to significant costs for homeowners.