The Fairfax County Water Authority is becoming the public agency that many Northern Virginians, including the region's political leaders, love to hate.

After years of operating in relative obscurity, the authority is in a well-publicized state of siege. Compounding the atmosphere of crisis is the prospect of a serious water shortage for the authority's 612,000 customers as its Occoquan Reservoir continues to recede to record-low levels.

Whenever the agency makes a decision - big or small - its critics seem to pounce on it with accusations that its astions are "astounding and incredible," and "sheer adventurism."

So upset did the Fairfax County Board of Supervisors become over the manner in which the largely autonomous authority decided to build a $53-million water-treatment facility on the Potomac River that the supervisors considered taking over the agency. They finally settled for enlarging the board of commissioners from five to nine in hopes of going more control over the agency. The supervisors appoint the voting members of the authority.

Prince William County, which is a major customer of the authority but has no voting power on the board, is attempting to create its own water-supply system by impounding Cedar Run in western Prince William. If the county's move is successful the Occoquan Reservoir, the authority's only major source of water, would lose one of its major tributaries.

Two weeks as authority leaders were subjected to the humiliating spectacle of being summoned to the office of Fairfax Board Chairman John F. Herrity to justify their staff's proposals to spend $10,000 on greenery and $5,000 on art for the agency's new offices.

In recent months the water authority has been accused of ignoring the potential threat of chloroform, a suspected human carcinogen, in its water; failing to develop a water conservation policy even though the state has said a critical shortage is impending, and failing to promote controls on storm-water runoff, which has been identified as the major source of pollution in the Occoquan.

On the issue of storm-water runoff, Fairfax Supervisor Audrey Moore (D-Annandale) said of the authority: "They ought to be horsewhipped for the way they have failed to act."

Water authority officials defend their agency on the caliber of its personnel.

"I deal with public utility officials around the country," said William J. Madden, an attorney who was recently appointed to the board. "And I can say, the staff here is second to none."

Bill G. Evans, a veteran board member who is a management consultant, said that when the Authority does something good, people don't seem to notice. "There probably aren't a handful of people who know that since 1974 we've had a rate schedule under which new customers, and not old ones, pay for future capital improvements."

While the supervisors complained about $5,000 allocated for art in the new offices, authority members bitterly recall that in 1974 the supervisors rejected the authority's original site for the Potomac River filtration plant, thereby adding an estimated $4.7 million to the project's cost - or about 20 times the price of all the furnishings of the new headquarters.

What is troubling to many critics is that the authority is not accountable to the residents of Northern Virginia who are its customers, or to the region's political leaders. In fact, by its own admission, the authority is most directly accountable to its bond purchasers in New York.

The powerful leverage of Wall Street became apparent when the authority recently explained why it was seeking its second rate increase. In four years - seven years ahead of schedule.

As the authority explained, when it issues revenue bonds to raise capital for construction it must enter into "trust agreements" with purchasers. These agreements mandate rate schedules that not only insure that the authority will have enough money to pay off the bonds but provide a 10 to 20 per cent "margin of safety." Furthermore, such rate schedules are required for a 10-year period to cover planning, construction and operating expenses.

Last year the authority was bluntly told by Wall Street that there would have to be a hefty increase in customer charges if the agency hoped to float a new bond issue at reasonable interest rates.

The authority is at Wall Street's mercy because the agency issues revenue bonds, whose payment is not underwritten by taxpayers as are the general bonds issued by Fairfax County and other local governments.

But while the authority has been criticized for not being accountable enough to the people it serves, its creators the Fairfax Board of Supervisors endowed it with the autonomy it enjoys.

One of the reasons, according to long-time observers, is that the supervisors did not want expansion of water supply in the fast-growing county subject to the vagaries of voter sentiment on bond referendumns. The authority's revenue bonds do not require voter approval.

But since the authority was created in 1966, many circumstances have changed, and almost always to the agency's disadvantage.

Most importantly, there has been a tempering of the rapid-growth philosophy in Fairfax. This has sometimes led to conflicts between the supervisors and the authority, which must steadily grow to pay off the authority's enormous debt. The debt costs close to $8 million annually now, and will reach $12.4 million by 1979.

Secondly, the authority's original task - to supply an adequate amount of potable water to its customers has been complicated by a variety of environmental and political factors.

The Occoquan Reservoir, which can store up to 9.8 billion gallons of water, now has less than half that amount. Voluntary water conservation requests by the jurisdictions served by the authority (Alexandria, most of Fairfax County and part of Prince William) have met with little success in reducing consumption.

(While the Occoquan's water level has steadily diminished in recent weeks, the Potomac River is providing a comfortably safe margin of surplus water for the more than two million Washington-area residents who depend on it.)

The Occuquan Reservoir is also the catch basin for sewage effluent from Prince William and part of Fairfax. When the new regional sewage-treatment plant opens next year on Bull Run, almost 11 millions gallons of effluent will pour daily into the reservoir.

The sewage-treatment plant, which is replacing a number of smaller, older ones, will provide a high degree of treatment. But even if the effluent, does not degrade the reservoir, new development will have an adverse impact in other ways, primarily through storm-water runoff.

A long-term monitoring program has shown that runoff from urban areas, such as parking lots, streets and gutters, is funneling a wide range of pollutants into the reservoir. Storm water, unlike sewage, is not treated before it reaches the reservoir.

Just as the authority has become entangled in environmental issues, so it has become mired in politics. The uproar over the furnishings porposed for the authority's new offices was a prime example.

Informed that the agency planned to buy all new furniture and related furnishings because the new quarters would have an open enviornment, Supervisor Martha V. Pennino said, "It's so astounding and incredible that it leaves me gasping."

Water commissioner Thomas C. Rowan shot back that the county spends $18 million annually on police but "the county police's rate of solving crimes is well below the national average."

A potentially much more serious potical problem involves the authority's attempt to start taking water out of the Potomac River as a supplement to the Occuquan. Though the authority has already spent millions of dollars to acquire land and begin preliminary work, it still doesn't have the [TEXT OMITTED FROM SOURCE]