A dispute in Reston over whether the homeowners' association should accept responsibility for two of the town's scenic lakes, was defused last week when Reston Land Corp. officials promised to pay for upgrading the dams on Lakes Audubon and Thoreau.

Francis Steinbauer, president of the Mobil Oil Corp. subsidiary that is completing the development of Reston, agreed at a public meeting that Reston Land would pay for any improvements to the dams that might be required by the state Water Control Board. The state board is expected to license the two dams for operation in the near future.

The controversy over whether the dams were safe has simmered for years, but sparked recently when the board of the Reston Homeowners Association (RHOA) decided to consider accepting ownership of the dams earlier than scheduled. RHOA, which was established by Reston Land to maintain the planned community's open space and recreational facilities, is still under developer control and has routinely taken over responsibility of Reston's developed amenities.

Some of RHOA's dues-paying members, however, claimed that the dams were unsafe, and accused RHOA's governing board of rushing to accept dams that could require costly repairs in the future. Under the terms of RHOA's charter, Reston Land maintains control of the association until 1984, when the majority of the development will be complete, and some homeowners wanted the decision to accept the dams delayed until the residents controlled the RHOA board.

But this week's public hearing appeared to dilute the protests of those homeowners concerned about the dams' safety, and Steinbauer's promise to commit funds to upgrade the dams was warmly received by the RHOA board.

"We have made every possible effort to look into every nook and cranny and we are confident that the dams were designed to the best known standards and are safe and healthy," said Steinbauer. "We've made a commitment to RHOA to do whatever is required by the state Water Control Board to obtain maintainence and operating permits for the dams."

Engineering studies commissioned by Reston Land concluded that both dams were structurally safe and that the chances of failure and flooding were remote, findings corroborated by an engineering firm brought in by Fairfax County to analyze the studies.

But the studies did identify problems, primarily whether the dams met state standards, and residents present at the hearing wanted to know what could be done to protect the homeowners' association from future expenses.

According to George Sowers, a nationally recognized dam expert and one of the engineers consulted by Reston Land, the Lake Audubon dam was found to be able to withstand 75 percent of a Probable Maximum Flood and Lake Thoreau's dam, 85 percent. A Probably Maximum Flood is defined as 36 inches of rain in 24 hours, "far more than has ever fallen in the state of Virginia," said Sowers.

"That's next to Noah, and with that kind of rainfall many homes downstream would already be flooded by 17 feet of water," said Sowers. "If the dams failed, it would add another two feet of water."

When the dams were built in the late 1970s, both met Virginia's standards for dams with houses downstream. But those regulations are being rewritten and RHOA members said they feared stricter standards would require additional construction on the dams, at RHOA's expense.

In response to that concern, Steinbauer also agreed to give RHOA $107,000, to be put into an escrow account, to improve the dams on both lakes if the state decides to raise the standards for high hazard dams.

While there were still protests from some RHOA members that Reston Land should go even farther to ensure the safety of the dams, many residents appeared pleased by Steinbauer's commitment. The RHOA board is expected to vote on accepting ownership of the lakes and dams in two weeks so that, as board member Clive Blackwell said, "we can get on to other controversies."