Two weeks after a Mt. Airy, Md., couple paid a Hagerstown, Md., paving company $1,000 to resurface their driveway, the couple noticed dandelions popping through the new blacktop, making it crack in every direction.

Several weeks after Potomac woman gave a Silver Spring contractor a $10,000 down payment to convert her patio into a family room, the contractor disappeared, leaving the room unfinished, live electrical wires dangling outdoors and debris scattered everywhere.

And four months after a Prince George's County man paid a $1,000 deposit to an Oxon Hill contractor to install storm doors and windows throughout his home, the man was still waiting for the windows. Meanwhile, January had turned to May.

According to recent estimates, Washington area residents spend about $500 million a year on home improvements ranging from aluminum siding and weather-proofing to extra bathrooms and family rooms. As the home improvement industry has burgeoned here and elsewhere around the country, so, apparently, has the number of unskilled, unlicensed or unethical contractors.

The problems of the Mt. Airy couple, the Potomac woman and the Prince George's County man are typical of complaints received by the Maryland Home Improvement Commission, the state agency responsible for licensing contractors and handling consumers' complaints against them. In the past decade, the cases handled by the commission have more than doubled, from 768 in fiscal 1968 to 1,614 last year.

Despite the increase, consumer advocates estimate that these cases represent only a fraction of the number of homeowners cheated by home improvement contractors. Many Maryland homeowners don't realize that they have recourse with a state agency, it is believed.

In addition, the commission had been having its own problems. Two weeks ago, acting Gov. Blair Lee III removed its long-time chairman, Charles J. Harrison, and publicly criticized the other members for what he described as "intolerable" conduct.

Lee charged that he had received numerous complaints from people who had appeared before the commission that the members did "everything but listen to them - gossip among themselves, read newspapers, even go to sleep."

Although the commissioners deny ever having read newspapers or fallen asleep during a hearing - two members sent angry letters to Lee protesting his criticism - James L. Dyson, the most recently appointed member of the commission, concedes that there is room for improvement.

"Obviously, it hasn't been doing a good job, or at least as good as it could do," said Dyson, who, as head of the home improvement division of the Montgomery County Office of Consumer Affairs, was an observer of the state commission for several years before joining it last July.

Dyson added that one of the biggest problems with the commission in the past has been the constraints of Maryland's home improvement law. Under it, the commission in many cases can force contractors to return to jobs to finish imcomplete work or to make repairs by threatening to suspend or revoke their licenses.

But the commission has no power to award monetary damages to homeowners if the contractors refuse to comply with the contracts. Instead, the cases are referred to local state's attorney's offices for prosecution, and the homeowners must go through the expensive and time-consuming process of filing lawsuits to recover damages.

Changes in the current law that were adopted by the General Assembly and go into effect Jan. 1, however, will substantially broaden the commission's power to help consumers.

Among the most significant is a requirement that all home improvement contractors in the state be bonded - or show proof of financial security - before they can obtain a license.

This means that if a contractor abandons a job, or goes out of business for financial reasons, the commission can award a homeowner up to $5,000 in damages after a hearing.

(The District of Columbia and most Northern Virginia jurisdictions already have similar provisions in their home impprovement laws.)

"The new law is going to make things a lot easier," said Dyson. "In the past, the consumer got nothing. All the commission could do was take away a license. People would drive all the way from the Eastern Shore or Frederick County (to Baltimore) thinking the commission could help them get their money back. It was very frustrating for a lot of them."

W. Robert Wallace, whom acting Gov. Lee appointed to replace Harrison as commission chairman, added: "With the new law, it looks as though there really is some chance for justice... some opportunity for action to help the consumer."

According to its executive director, James A. Morkosky, many of the more than 14,700 complaints filed with the commission since it was formed in 1962 have been resolved without a hearing, simply by pressuring a contractor into complying with a contract.

In one case, for example, records show that a Silver Spring woman had tried unsuccessfully to reach a contractor who had installed a aluminum sliding on her home but had failed to ground it. Finally, the woman left a message with the contractor's answering service that she had referred her complaint to the Home Improvement Commission. The contactor returned her call immediately and set up an appointment to finish the job.

A warning letter from the commission also brought results for the Mt. Airy couple, who were satisfied after the paving company repaired their driveway.

Of those cases the commission cannot resolve - usually those in which the homeowner wants a refund - most are referred to the state's attorney's office in the owner's county for possible criminal action. As a result of these referrals, Morkosky said, homeowners have recovered more than $250,000 in damages since 1962, But Dyson points out that this is a small percentage of what they have lost on incomplete or shoddy work.

Another way the commission can help a consumer is by giving him or her information about contrator's qualifications before a contract is signed. By calling or writing the commission, the homeowner can find out if the contractor is licensed, how long he or she has been in business and whether these are any outstanding complaints against the company.

An outstanding complaint is the most frequent reason for the commission to revoke or suspend a contractor's license, which must be renewed annually under the law. But the commission can also deny a license or renewal application if the contractor has been convicted of a serious crime.

Despite the accessibility of information about the records of Maryland's 10,017 licensed home improvement contractors, Morkosky said he is constantly surprised by the number of homeowners who hire a contractor without first checking to see if the contractor is licensed.

Morkosky added that he has noticed an increase in the number of unlicensed contractors in the past few years. He attributed this to a rise in unemployment and to the growth of the home improvement industry in general, as more and more people opt to improve or add on to their homes rather than move to more expensive ones.

"When you hire a contractor, It's like giving him a key to your home, really," Morkosky said. "People should be aware that there are risks involved."

"It's a damn shame that some of the people are so naive to be taken in by these gypsy contractors who take their money and disappear," added Del. Francis J. Santangelo, (D-Prince George's), principal sponsor of the new state law."The really sad thing about it is that many of the victims are older people."

Since most people aren't aware of the pitfalls of home improvement until it's too late, the new law offers another safeguard for the consumer against unlicensed contractors. It requires the Home Improvement Commission to furnish lists of licensed contractors to all local agencies responsible for issuing building permits.

This was designed to prevent an unlicensed contractor from getting the permits required for most major home improvement projects.

Another provision prohibits the contractor from requiring a down payment of more than 30 percent of the total contract. This gives the homeowner some financial leverage if the contractor abandons the project.

Although changes in Maryland's home improvement law could significantly benefit homeowners, Dyson cautions that total regulation of the industry is impossible. As a result, home improvement is another area where the buyer should beware.

"It's the type of industry you'll never clean up completely," said Dyson, "because no matter what you do almost anybody can call himself a home improvement contractor. What you'd really need is about 25,000 employes on the Home Improvement Commission checking out everything that's done. But as a practical matter, it doesn't work that way.

"You just have to hope that the consuming public will be intelligent enough to protect themselves."