Maryland's 17th legislative District spans Rockville, Wheaton and Potomac, and, in a sense, it embraces three different worlds.

There is the world of the blue collar workers and middle-level government employes, who for the most part, have lived in the district for several years. They are likely to reside in the modest $40,000-to-$50,000 single-family homes built around World War II that line the streets of the Veirs Mill Road corridor.

Their children are grown in many instances, and schools are closing in their neighborhoods. Their income level has reached its peak, yet their home assessments continue to rise.

They are concerned about the way their taxes keep going up faster than their ability to pay.

Many of them are union members concerned about labor causes. They tend to be Catholic, and to vote Democratic for the candidates who best fit the label, "conservative"

Abortion is an issue here.

Then there is the wealthier, younger group of Democrats that have moved recently to the newer subdivisions of the district: Fox Hills West, Copenhaver, Potomac Springs, Horizon Hill.

They are professionals, for the most part. And theirs are the wide-lawned $100,000 homes set along the cul-desacs on the outskirts of Rockville and in northwestern Potomac.

There are three cars in some driveways, and a warning to burglars on the front door. Sometimes there's an intercom attached to the front door so they never have to open the door to talk with strangers.

Crime is an issue here.

There is also a small, but varied group of Republicans in District 17. They are as likely to live in the older, less exclusive neighborhoods in Rockville as they are in the most expensive subdivisions in Potomac.

Yet in general, according to political observers in the district, they are traditionalist Republicans, supporting less government and less government spending.

"I think the district can best be described as schizophrenic," said Lanny Davis, the 32-year-old Democrat who ran unsuccessfully for Congress in 1976 and 1974, and lives in the district.

Traditionally, District 17, along with 15A in the Damascus area, has been considered a conservative stronghold.

Of its registered voters, 30.3 percent are Republicans. For the county at large, Republicans account for only 26.6 percent of the voters. Thus Republicans have traditionally considered 17 a "swing district," one just as likely to elect a Republican as a Democrat.

But the district has added some 700 new homes since the last election, which means about 1,400 to 1,600 new voters may be voting in the upcoming elections. The ratio of registered voters in the new subdivisions are 2-to-1 Democratic. Many political observers say the newcomers appear to be more liberal voters.

But whether these newcomers will make their liberal presence felt in the upcoming election by voting, is an open question.

If there is one issue that bridges the "three worlds" of District 17, it is taxes. Candidates, whether they are Republican or Democrat, conservative or liberal on social issues, are all calling themselves "fiscal conservatives" as if theat is the catchword that can get them elected.

"It's just not important - a candidate's stand on the social issues. They want to know where I stand on fiscal issues," says Brian E. Barkley, a Democratic candidate for the House, who's been going door-to-door, talking with voters about their concerns.

Yet, the question of state funding for abortion still shadows this election district, which has one of the county's largest Catholic populations. Most of the candidates are Catholic and agree the abortion issue could make or break them. Last election, some Catholic parishes distributed lists naming "prolife" and "proabortion" candidates.

In the primary race for the state Senate both the Democratic and Republican candidates are running unopposed for their parties' nominations. In the House race, Democratic voters must choose three nominees from among eight candidates. Only two Republicans are running in the primary, so they will be their party's nominees in the general election.

The three incumbents in the district are all Democrats. Joseph E. Owens and Robert Anthony Jacques, both Rockville lawyers, are running for reelection to the House of Delegates. Del. S. Frank Shore is running for state Sen. Charles Gilchrist's seat. Gilcrist is running for county executive.

Owens is perhaps the most consistently conservative of the group. He voted against Medicaid funding for abortion, opposes collective bargaining for county employes, and supported capital punishment and state pension reform.

"Some liberals would call Joe Owens' voting record Neanderthal, said one Democratic supporter, "but he is as honest as the day is long."

"I had a problem with too much government and too many laws," says Owens, a gruff-speaking retired Army colonel.

S. Frank Shore, an employe of the C&P Telephone Co., is considered unbeatable by many Democratic observers. His forte is politics with a personal touch, rather than heated debate on the House floor, his colleagues say. And the walls of his office in Annapolis are covered with photographs from functions he's attended where he has presented the American flag, or the flag of Maryland.

"Frank doesn't antagonize people," says his running mate Jacques.

Jacques, on the other hand, admits he is sweating out his reelection bid. He is handicapped, to a degree, he says, by his image of being the argumentative, artfully sarcastic iconoclast of the delegation.

His supporters, however, maintain that a man like Jacques, with a refreshing knack for underscoring the failings of the legislative and the quirks of its members, is just what's needed in Annapolis.

The challenges in the district are as diverse in their backgrounds as the district is varied.

Republican Albert N. Nunn is running unopposed against Shore for the Senate seat. He is an American Airlines pilot who ran for Congress in 1976, and maintains that Shore's actual contribution to the legislature has been minimal in the past eight years. Luiz Simmons, a liberal Republican who lost by about 600 votes in the last legislative race, and Eleanore Arn, who is active in county pledges to be a full-time legislator, and Charles Schmidt, former lobbyist Republican organizations and believes more women and a more practical approach to problems is needed in the assembly, are running for the House.

Democratic candidates for the House also include: Jennie M. Forehand, a Rockville citizen activist who is a member of the county health systems planning agency and state mental health board; James G. Kolb, the lawyer who is handling the court case to get the abortion funding question on the ballot, and Brian Barkley, a Silver Spring lawyer who has picked up support from former Lanny Davis supporters. Other Democrats running for the House are Paul McGuckian, former counsel to the Montgomery delegation; John W. Tower, who for the Veterans of Foreign Wars, and commander of the Montgomery County chapter of the VFW.

Independent George R. Laney is running on a prolife platform.