With Dirtmarket, a Campbell-based online exchange, David Rossi and Lesley Matheson fill the needs of contractors and landscapers alike who have either too much or not enough dirt on their hands. And in the process, the couple is changing the way people look at the ground beneath their feet.

"We've been called a dating service for dirt," Dirtmarket co-founder Rossi said. "Basically, we help match people who have dirt with people who need it."

The concept of the service is a simple one, he said. Suppose, for instance, someone dug a hole in his backyard for a new swimming pool. He would have to do something with the dirt that he'd displaced. Normally the homeowner would have to pay someone to haul it away and dump it into a landfill. Suppose also that someone else was looking to fill in a pool that she had in her own backyard. Normally, she would contact a landscaper, who would most likely get the dirt from a rockery.

But the idea for Dirtmarket is to make it possible for the man wanting to get rid of his dirt to sell it to the woman wanting to procure some.

"We basically allow that to happen," Rossi said. "But we do it on a much larger scale."

He said most of his business has been with mid-to-large-size contractors working on projects.

Whether it's a large job or small one, however, using the service is "a win-win situation," co-founder Matheson said.

The buyer can usually get the dirt cheaper than at a traditional supplier's, and the seller wouldn't have to pay to throw away perfectly good soil.

"People don't understand the scope of the recycling aspect," Matheson said. "But it does have a huge impact, and it's one of the most rewarding parts of my job."

She said that about 30 percent to 40 percent of all landfill waste comes from construction sites. And about 30 to 50 percent of construction waste comes from earthworks.

"A lot of it is clean, reusable stuff, too," she said. "Our company can help keep landfills from filling up with clean material, and we can usually save costs for everyone."

The idea for their company came about four years ago, when Rossi, a commercial contractor, was working on a project to build a small hotel. Rossi put the basement-digging phase of the project out to bid. As originally planned, the displaced dirt at the construction site was supposed to go to a landfill.

"But the people doing the digging said that if we could slow down our timetable and help them find an alternative place to take the dirt, it could probably save us a lot of money," Rossi said.

He decided to wait.

Unlike other commodities, dirt has procurement costs as well as disposal costs, he said.

"You don't find many people paying to get rid of wood," Rossi said. "But it does cost a lot of money to dump dirt into a landfill."

As Rossi struggled to make all the phone calls to locate a dirt buyer, Matheson, his wife, watched on. Despite the hard work, both of them felt the effort was good for the business.

Eventually Rossi located someone.

"Because we took the time to find a trade, we saved about $80,000," Rossi said.

The experience gave the couple an idea. They could create a business that would match people who want dirt with those who want to get rid of it. But, they thought, there had to be a more efficient way of doing it than just calling people. They found their answer in technology—namely, the Internet.

In 2000, they founded Dirtmarket as an online exchange. There was no other business around like it, Rossi said. Some truckers actually provided the service through trucking jobs, but until the two started Dirtmarket, there was no organized exchange.

"In every project, workers have to find dirt or get rid of it," Matheson said. "David explained to me how expensive it was to get rid of the dirt on the project, and he described how neat it would be if there were an online exchange available to help you find anyone who wanted what you had in, say, a 10- or 15-mile radius."

Matheson, who earned a doctorate in computer science from Princeton, immediately thought "that's easy" and created the website to do just that. Since then, the company has grown about 300 percent annually, and its services cover almost all of California. Dirtmarket now has a staff of about 16 people, and it has branched out to include a more varied set of products and services.

"We found that just throwing technology out there wasn't good enough," Matheson said. "Dirt can be complicated, because soil isn't just soil. There are scores, if not hundreds, of different types of soil that people need to work with and be aware of. And a lot of times, we have to do a lot of work negotiating between the two owners."

Moreover, Rossi said, the soil must go through a battery of tests before it is approved for use in different project sites.

"We do a lot of work with the Department of Toxic Substance Control," Rossi said. "We don't even move dirt if we don't have the correct environmental toxic repots. We actually test materials for everything."

Rossi said the company is mostly about being able to match exchange members' needs, but it helps out even if it cannot make the match.

"We give people options and answers," he said. "For example, if someone wants to get rid of dirt and no one wants it, we provide the places where this can be done. If you got to move it, you got to move it. But if you can wait, chances are you can find a deal. And we can help you find matching trades."

Scott Tavares, a landscaper with San Jose­based Field of Dreams, is a regular customer.

"It's great," he said. "Whenever I need something, I just call them up and they deliver. What I like about them is that their prices are right in there. They're a lot cheaper than rockeries', and I never have an issue about them not finding what I need."

In the last few weeks, the company has launched a pilot program called Bulk Express in 13 Home Depot stores throughout the Bay Area, including one at the Campbell location. The service lets even small landscapers and gardeners take advantage of the Dirtmarket technology.

"We've had a lot of inquiries to take this to other markets," she said. "But we've pulled in the reins with that kind of growth."