The well is running dry for "Superfund" cleanups this year, and the Environmental Protection Agency's regional offices have been told to cut back on non-emergency expenditures.

Lee M. Thomas, assistant administrator for solid waste and emergency response, told regional administrators in a memorandum Monday that they will have to live within a ceiling until the beginning of the fiscal year Oct. 1, when the agency will get a new, larger infusion of Superfund money.

"There is a concern that unless we manage very closely, we could be in a shortfall situation and could not respond to unexpected emergencies," Superfund director William N. Hedeman said yesterday.

Hedeman said there is money for emergencies now, but he couldn't say how much. "We may have to juggle accounts back and forth," he said, "but I don't see that we're in a bind at this point."

EPA officials say the money crunch is largely a result of the government's buyout of dioxin-contaminated Times Beach, Mo., which took $33 million of the $190 million allocated this year for Superfund cleanups.

But the agency also has been considerably more efficient in spending cleanup money in the last two months, since Administrator William D. Ruckelshaus took office and told regional officials to get cracking on the worst of the hazardous waste dumps in their areas.

In the first eight months of the fiscal year the EPA spent $11 million on emergency actions to remove immediate health hazards and $32 million for long-term cleanup work. In the past two months, the agency has spent $12 million on emergency cleanups, and Hedeman says he expects the agency to obligate an additional $48 million for long-term cleanups before Sept. 30. GROUND WATER ROILING . . . Impatient with the EPA's efforts to draw up a national policy on ground water, a bipartisan group of congressmen headed by Rep. Bob Edgar (D-Pa.) has introduced a bill to create a 17-member, $7 million national commission to come up with some answers.

The commission would have until late 1985 to make its recommendations. But some congressional supporters figure that will still bring it in well ahead of the EPA's policy, which shows no sign of surfacing more than two years after the Reagan administration started working on it.

In May, 1982, former Superfund chief Rita M. Lavelle told a House panel that a blue-ribbon study would simply delay EPA's efforts. But when the EPA did come up with a draft policy early this year, it failed to win approval in the Cabinet council chaired by Interior Secretary James G. Watt.

Watt "stated that his 'instincts' told him a ground-water policy might threaten states' rights," Edgar said at a news conference yesterday. " . . . I feel that it is time we stopped relying on Secretary Watt's 'instincts' and Rita Lavelle's promises on this matter." Lavelle's contempt-of-Congress trial opened yesterday. Story, Page A2. CHEMISTRY SPOKEN HERE . . . The room was awash with logarithms this week at the National Academy of Sciences, where 15 experts on acid rain were debating the merits of their research for Ruckelshaus' benefit.

While the scientists bandied cations and cloud chemistry, sulfur loadings and metal chelates, Joseph A. Cannon was on the sidelines, struggling valiantly to stay afloat. Cannon, EPA policy chief under former administrator Anne M. Burford, is now in line to be assistant administrator in charge of the air division, where any acid rain program will come home to roost.

"I used to deal mostly with cost assessments," he sighed during a break in the action. "I'll have to read a transcript of this pretty closely."