ISIAH LEGGETT, Montgomery County executive, has a reputation as a master dealmaker. He showed his stripes shortly after taking office some weeks ago by settling a noxious dispute over the location of a day-laborer center, artfully finessing protests from the city of Gaithersburg by placing it just beyond city limits. Now he has cut a deal involving a trouble spot with a long and sorry history of corruption, the Washington Suburban Sanitary Commission. But is Mr. Leggett's latest deal a good one?

The largest utility in the Washington region, the WSSC provides water and sewer services for more than 1.6 million customers in Montgomery and Prince George's counties. It is also a wellspring for tens of millions of dollars worth of contracts each year for a staggering array of construction projects, engineering work, and technical products and services. Little wonder, perhaps, that its history is checkered with episodes of political meddling, favoritism and graft.

That bitter legacy explains the curious history of a 115-acre parcel owned by the WSSC that has been the focal point of a long-running dispute between the agency's two masters, Montgomery and Prince George's counties. The property, known as Site II, is a former sludge-processing facility in eastern Montgomery that has sat abandoned for eight years. Unneeded by the WSSC, the land is seen by county planners as a perfect site for a science and technology office park. Its location off Route 29 near the Food and Drug Administration's new headquarters at White Oak could make it a magnet for businesses. Montgomery officials estimate that the office park would attract 2,000 new jobs to an area that badly needs them.

Yet what seemed like a fine idea has been hung up for months by opposition from WSSC commissioners appointed by Prince George's, who blocked the agency's sale of the tract to Montgomery. Their stated reason was price, but that was a smokescreen. What the commissioners wanted was control over the WSSC's Small, Local and Minority Business Enterprise Program, which has been a fountainhead for patronage and influence-peddling. The commissioners demanded that rather than report to the utility's general manager, like every other agency at the WSSC, the program should report directly to them, making it more susceptible to special deals for the politically well-connected. To get what they wanted, the Prince George's commissioners, backed by County Executive Jack B. Johnson, held hostage Montgomery's purchase of Site II.

Enter Mr. Leggett. Making quick work of an impasse that had dragged on for months, he sat down with Mr. Johnson and agreed to split the difference: The WSSC will sell Site II to Montgomery County; in return the business enterprise program will report to both the general manager and the commissioners.

This dual reporting arrangement is an imperfect fix, as Mr. Leggett himself acknowledges. It invites political mischief with contract decisions of the sort that has plagued the WSSC. At the very least, it will saddle the commissioners, who should be setting policy and planning for the long-term needs of customers, with day-to-day managerial detail. Mr. Leggett has made a calculated bet that the potential benefits of developing Site II will outweigh the potential for embarrassment inherent in his deal. We hope he's right.