TAMPA - South of the Alafia River, new houses and sodded lawns spread like kudzu along the U.S 301 and U.S 41 corridors.

"The people are outnumbering the blades of grass,'' said Aldyce Garms, president of Concerned Citizens of Gibsonton.

She's laughing, sort of, when she makes this observation. But in fact, the 14-year Gibsonton resident lives in the vortex of the busiest real estate market in the county.

South Hillsborough is the new Brandon and the new northwest Hillsborough, once rural frontiers that have grown saturated with houses, apartments and shopping malls.

Now developers have set their sights on the south end, which is expected to absorb a fair share of the 17,500 additional residents projected to settle in Hillsborough each year for the next 23 years, adding an estimated 402,500 people.

"There are people who don't want any growth. They don't want any development,'' Garms said. "That is not going to happen.''

By 2025, the county population will approach 1.5 million, according to projections from the Hillsborough County City-County Planning Commission.

Those residents will expect water to run from their taps and sewage to disappear down drains. They will need schools, parks, libraries and roads, the building blocks of development.

So where will the money come from to pay for this?

Now it's coming from gas, sales, property and other taxes, as well as impact fees, one- time payments developers make to offset the cost of infrastructure and services that support what they build.

But a battle is brewing over whether developers are paying their fair share and who will foot the cost of further growth.

A recent planning commission survey found more than two-thirds of residents say the costs are not fairly distributed and most of the money should come from impact fees.

Passed On To Home Buyers

Developers point out that impact fees, which took hold in Florida after 1985, are not charged by every county. Some opt for the traditional mix of sales, gas and property taxes to pay for growth.

As of 2000, 31 of the state's 67 counties did not charge impact fees, according to Florida's Legislative Committee on Intergovernmental Relations.

However, more counties are considering the fees. For example, Polk County commissioners approved a first-time school impact fee, effective Sept. 1. Polk voters also approved a half-cent sales tax for school construction.

Developers say the fees, which are passed on to new home buyers, stifle growth and price some residents out of the housing market.

Impact fees can add as much as $8,000 to a home's price, said Joseph Narkiewicz, vice president of Tampa Bay Builders Association. In Hillsborough, that would include roughly $2,000 in impact fees for roads, schools, parks and fire protection, plus the cost of water and sewer hookups, which the county calls "capacity fees.'' They add $5,000 to $6,000 to the home's price.

Regardless of what they are called, the home buyer ultimately picks up the tab.

"They can be priced out of the market very easily,'' Narkiewicz said.

The biggest share of the fees is for road work.

"It's just a matter of managing the budget, meaning the resources,'' Narkiewicz said. "Impact fees alone cannot generate income you need to completely pay for roads.''

Other taxes, such as gas tax, sales tax and user fees, can better spread the cost of growth to everyone who benefits, he said.

Shifting The Burden

During the past 15 years, inflation has eroded the share of the road bill paid by developers.

Where developers once paid 85 percent of road work related to new growth, a county study placed their contribution at 16 percent in 1999.

That share probably is closer to 12 percent or 13 percent today, said Jim Hosler, research director for the planning commission. Commissioners have not approved adjustments to keep up with the rising costs of road construction, he said.

"I believe there is a real funding shortage caused by the inability of local officials here and across the state to address the issue,'' Hosler said.

County Commissioner Jim Norman says he's keeping an open mind on raising road fees.

"I want to see what we can do with our existing budget,'' he said.

Three years ago, a citizen- based group, the Committee of 99, recommended increasing impact fees as well as gas and sales taxes to pay for a range of transportation projects.

Last year, the Greater Tampa Chamber of Commerce weighed in with a proposal to increase road fees 10 percent per year for the next four years, but only if gas and sales taxes also go up. Commissioners could opt to put the issue to voters in a referendum in November 2004.

Hosler said proposals to raise fees traditionally have met with stiff opposition from developers without generating as much heat from the public.

"I don't think it rises to the level of health care and other issues the [county commission] addresses,'' he said.

Hillsborough already has $2.1 billion in unmet transportation needs projected for the next two decades.

Thursday, the county will hold the first in a series of transportation summits that by fall could lead to a vote by commissioners to increase road fees.

Land-use lawyer Ron Weaver said commissioners have the power to increase the gas tax without a referendum.

"If you increase the impact fee too much, people will hurry off to Pasco,'' said Weaver, who is chairman of the Tampa chamber's committee on land use and economic development.

Commissioner Pat Frank doesn't buy that argument.

"I don't know that anybody isn't buying homes here,'' she said. "The roads here were built by people already here. They don't want to pay for them again.''

The impact fees for a three- bedroom single-family house in Hillsborough average $2,071, slightly higher than the fees in Tampa, at $1,967, and in Pinellas County, at $1,923.

Rising impact fees don't appear to be deterring home buyers in growth hot spots.

Pasco County, which is booming with development, charges $4,949 in impact fees. Manatee County, which charges $4,963, increased its fees about 25 percent in 2002.

Pinellas is increasing its road fees by 18 percent during the next two years.