Washington area developers and their lawyers yesterday applauded a Supreme Court decision entitling property owners to compensation when government regulations won't let them use their land, but said they doubt that local courts will be swamped with related lawsuits.

However, lawyers and planners for local governments warned that the decision may discourage actions to protect the environment and public health and cited recent Maryland legislation to protect the Chesapeake Bay as the type that governments might hesitate to enact in the future.

Smaller jurisdictions that could not afford costly lawsuits or large damage awards would be particularly wary of adopting such laws, according to local government lawyers.

The decision Tuesday in a California case exposes state and local governments -- already buffeted by soaring liability insurance premiums -- to potentially large judgments if courts determine that land use regulations amount to "a taking" without just compensation.

John Delaney, a land use lawyer in Maryland, and other analysts said that protracted delays and inaction by local governments in approving development plans could also be seen by the courts as tantamount to a temporary "taking" and thus be covered by the Supreme Court ruling.

In Montgomery County, for example, a local ordinance allows the county to block development plans if adequate public facilities such as roads, schools and sewer lines are not in place.

In the absence of a court test, it is unclear whether the Supreme Court decision would require the county to compensate developers for such a delay, said planners, zoning lawyers and others knowledgeable about the process.

While many developers were elated by the ruling, the court's failure to spell out what constitutes "a taking" makes it unlikely, in the short term at least, that the balance of power between property owners and Washington area jurisdictions will be significantly altered, experts said.

"The Supreme Court just kind of dropped a bomb with this decision," said one local county lawyer who asked not to be identified. "But it takes years for this stuff to get sorted out, with everybody litigating a different set of facts."

Marc Bettius, a well-known Northern Virginia land use lawyer, said, "This isn't going to be some sort of a panacea for developers to blackmail local governments with . . . . But it's a dramatic reaffirmation that property rights still have value."

In Maryland, worried environmentalists combed the decision for clues as to how it would affect the Chesapeake Bay legislation enacted last year. The so-called critical areas legislation imposes tough restrictions on landowners and aims to control residential development along the shores of the bay and its tributaries.

Under the program, in some areas near tidal waters on the bay and such tributaries as the Potomac River, regulations permit just one house per 20 acres -- a limit that landowners have protested adamantly.

"We're definitely worried about" the court's decision, said William C. Baker, president of the Chesapeake Bay Foundation. "The possibility is that this will increase the likelihood of lawsuits challenging {the law} and make officials in other states less likely to pass land use regulations that would benefit the Chesapeake Bay."

One major landowner in Charles County said he was heartened by news of the ruling. "It's a breakthrough for people who've been hurt by government regulations under the police powers," said Milton E. Canter, a Washington lawyer who owns nearly 5,000 acres of unspoiled land along the shore.

Canter said that while he had no plans to develop his property or to pursue litigation to overturn Maryland's restrictions on its use, he resented the state's actions, which he said "minimized the land's value down to being practically useless."

Courts in Maryland and other states have consistently upheld as valid local government rules that restricted the use of land if the rules were reasonable and in the public interest. Rules that have diminished the value of land have not automatically been deemed a taking.

Delaney said that for most state courts to determine that land has been taken without just compensation, "a regulation must deny the property owner of all reasonable use of his land."

For that reason, said Delaney, the application of the court's decision may be narrow, and unlikely to apply to downzonings and other government actions that are less than egregious.

"So much of the power the county really has is just to screw you up for years," said James R. Hardcastle, who publishes a newsletter about development in Fairfax. "Delay is really the chief weapon of the county in negotiating with a landowner."

Such tactics could be dampened by the Supreme Court's decision, he added.

In Fairfax County, where property owners' rights traditionally have been treated kindly by the Virginia courts, developers hailed the ruling as a warning to intrusive county regulators and a rebuff to growing antidevelopment sentiments among the public.

John T. (Til) Hazel Jr., a prominent Fairfax developer and lawyer, said, "It means that some of the excesses that have continued to creep into the system . . . will be harder to sustain. Some of the things we're seeing now are just a constant demand to control the development industry. That kind of activity is clearly jeopardized by the decision."

Hazel added that he has argued in favor of the primacy of property rights for years, and "I'm glad I've got some company like six Supreme Court justices."