"If we took all the studies that have been done on the Washington area water supply problem and threw them into the Potomac River, we'd have a dam," said J.J. Corbailis Jr., director of the Fairfax County Water Authority.

That quote, which has become a favorite among area water planners, decribes the frustrations of the fraternity of public officials who believe something must be done soon to improve the reliability of the area's water supply and to avoid summer-time shortages.

They have been unable to force decisions in a climate of interjurisdictional bickering and in the face of hostile opposition from citizens suspicious of big projects.

No solution is going to be cheap, whether it includes building a dam or the mandatory refitting of everybody's home and office with water saving plumbing fixtures. The water and sewer bill - like the electric bill - is going up.

A new round of studies - most prominently by the Army Corps of Engineers - is trying once again to project long-term regional water demands, study possible solutions, and figure out what each will cost.

In addition to dams. wells and conservation measures, the corps is studying seriously for the first time the question of whether the Potomac's polluted Tidal Estuary - the river below Little Falls - can safely be used as a water supply.

While regional studies are going on, some are beginning to doubt if a regional solution is politically possible. "The ideal regional solution," said Montgomery County Councilman John Menke, "is one that reduces the risk [of water shortage] to zero, costs nothing, and is in somebody else's county . . . I don't believe we're going to have a solution for the metropolitan area."

"Everybody keeps waiting for somebody else to move. We've now studying what would be the best way for Fairfax County to move," said Marie B. Travesky, a county supervisor.

John Salyer, an assistant corporation counsel who advises District of Columbia officials on environmental matters, said "I think ultimately the United States government will have to impose the solution."

The District sees itself as having no valleys to dam - no places to store water for use in dry spells - and thus as totally dependent on suburban good will, which is sometimes hard to find.

Complicating the already confused Washington area political process is the role of the Corps of Engineers. Under federal law, the corps is responsible for determining whether anything can be built in a streambed - such as the Potomac's. In Washington, and nowhere else, the corps also has the job of supplying water.

That dual role is regarded as a "conflict of interest" by Fairfax County Board Chairman John F. Herrity. The Washington Suburban Sanitary Commission (WSSC), and the Fairfax County Water Authority who along with the corps are the major water suppliers in the area - need corps approval for projects they want. to build right now in the Potomac River.

Fairfax wants to tap the Potomac as a water source for the first time - and needs the approval of the corps to construct an intake, but in dry periods there is not enough water in the river to completely cover the entrance to the pipe. That lets air into the system and reduces capacity. The WSSC thus wants to build a low dam to guarantee that water would cover the entrance to the pipe. In periods of normal river flow, the dam would not be visible.

Col G. K. Withers, Baltimore District engineer for the corps, has promised to make a decision on those construction permits by September. He stirred up a major fuss in February when he said a decision would take two years.

"The principal question which confronts me," Withers said in an interview, "is whether I can issue permits (for more water withdrawal) knowing that a potentially severe (water shortage) problem exists right now."

Both the Fairfax County and the WSSC projects are upriver from the water intakes for the corps' Washington Aqueduct - the water supply for D.C., Arlington and Falls Church.

To protect the aqueduct, the corps has insisted that the region's governments reach and sign a water-sharing agreement for periods of low flow in the Potomac. Such an agreement has been signed by everybody but the corps. Withers said there were some problems of equality in the water-sharing formula and that his lawyers were looking at it.

The corps in 1962 proposed 16 dams for the Potomac and its tributaries. Only three are even technically alive today. Only one is under construction.

That is the Bloomington Dam, on the North Branch of the Potomac, upriver from the Bloomington, Md. Assuming there are no more interruptions in funding, it will be operationally complete in 1980, according to the corps.

When completed, Bloomington can add 135 million gallons of water a day to the Potomac at Washington. Even though water from Bloomington will take about a month to get here, the corps says it is confident it can control the flow enough to provide a significant water supply safety valve.

Another dam, called Verona, has encountered ferocious opposition in Augusta County, Va., where it is supposed to be built on a tributary of the Shenandoah's South Fork, near Staunton. New geological information has forced a new site study. Most area water planners are betting privately that Verona, will never be built.

A third dam, called Sixes Bridge, on the Monocacy near Frederick, Md., is all but legally dead, pending the outcome of corps studies on other options.

With upriver impoundments out, area officials have begun looking at close-in reservoir possibilities to store water taken from the Potomac during high flow. Loudoun County suddenly became a very popular spot three years ago when a joint study of WSSC, Fairfax County and the District of Columbia concluded that a nice palce for a dam would be on Catctin Creek in Loudoun County.

The residents of Taylorsworn, whose area would be under water if such were to happen, complained vociferously. In the last two sessions of the Virginia legislature, Loudoun COunty delegates have put through bills that require the state-legislature to act before dams can be built on either Catoctin Creek or Coose Creek, another likely possibility for a local reservoir.

The most obvious solution to the Washington water supply problem, in the opinion of many conservationists and environmentalists, has been present for years. Right there today, beginning at the bottom of Little Falls, is the Potomac's Tidal Estuary.

Subject to the sloshing ebb and flow of the ocean's tides, it will never run dry. Its water does not become salty until Ft. Belvoir or below. why not take water from its upper reaches?

It is also the repository for the sewage effluent produced by the toilets and grabage grinders of 3 million Washington area residents, and that fact scares traditional civil engineers.

The corps is building a pilot water treatment plant next door to the Blue Plains sewage treatment plan, specifically to determine if the estuary water can be made safe to drink. The National Academy of Sciences will study the results. Construction, operation and study will last into the early 1980s. Then a decision must be reached on whether to build a fullscale plant.

In the meantime, at the top of the estuary near Chain Bridge, the corps is building a pump to lift water from the upper estuary to the Washington Aqueduct's water treatment plant. it will be used only in a major water supply emergency. It will be ready in the summer of 1978.

Louis Guy, of the Washington Chapter of the American Society of Civil Engineers, has been speaking for six years on the necessity of making a decision to ease the potential Washington water supply problem.

He thinks the lack of local decision-making has bordered on the irresponsible, and says so.

"If we don't make a decision before there's a drought, every consideration but speed will go out the window," he said. "That's stupid."