The super heroes in Virginia this summer have not been riding white horses, leaping tall buildings in single-bound or hitting towering home runs.

Instead, they've been cleaning water, blowing whistles, hosing down restrooms, fixing filters, enforcing rules and making deals with ice-cream vendor.

They are the area swimming pool managers, and rarely has a summer shown their value and job pressures as this one has. Because of this summer's severe heat, most pools have been used more often and by more people than usual.

"Whenever you have more people going to the pool you have more potential problems," says Mike Engley, manager of the Vienna Aquatic Club, a private community pool with approximately 450 member families.

Engley, affectionately known simply as "Boss" to his eight staff members, notes that increased pool usage has meant being constantly on the lookout for safety hazards as well as mechanical malfunctions.

"We have to watch for head-to-head collisions in the water," Engley says, "and kids jumping in without looking to see if anyone's in their way."

"Then there's running on the (cement) deck, where there's always a danger of people slipping and falling. Fortunately, we haven't had anyu serious on injuries."

One reason his pool's injury count is low is Engley's effectiveness as a disciplinarian.

"My theory of discipline is more like outrigh control," Engley says. "It's like something I'm responsible for the safety and welfare of all members. It works mainly because parents here give me and my guards a great deal of support."

Engley has a bench in front of his small office where offenders must sit, and he keeps a file of copies of the written referrals he sends to parents of youths who are discipline problems.

Not that Engley's pool is a watery concentration camp. On a recent 95-degree day adults, teenagers and todlers splashed, jumped and swam, happily and safely escaping the heat.

The object during this busy summer, managers point out, has been to keep the pools safe and clean. Cloudy water, which is not necessarily unhealthy water, can dishearten swimmers, so managers have hadd to add more chemicals and "backwash" the water and filters more often."

"Backwashing means sending the water out of the pool through the filters," explains Dean Sissler, manager of the Freedom Park pool near Tysons Corner. "That sends the water into a drain, and it's replaced in the pool with clean water. It only takes 15 to 30 minutes, and it can be done with people in the pool. But the problem is that it causes you to use more water."

At one of the Sterling Park Golf, Swim and Tennis Club's two 244,000-gallon pools, manager Pat Dolan and his staff faced an especially unpleasant water problem during one extremely busy hot spell.

"The water at one end started turning pea grean," Dolan says. "Nobody on our staff was quite sure what was causing it. We called the sanitation department, and they said it wasn't due to anything unusual in the water. Only one other pool in the area said they had had a similar problem, and they had to super chloriante (add a high amount of chlroine to the water.)"

Since upper chlorination meant closing the pool for eight hours and risking the wrath of the membership, Dolan, convinced there was no health problem, "relied on an old standby. The rule is that whatever your water turns colors, try aluminum sulfate to clear it up."

The aluminum sulfate worked. The pool didn't close.Everyone was happy.

Still, as summer's final weeks draw near, the heroes live in fear.

"The biggest worry is that on a really hot day the pool's pump motor will burn up," says Sissler. "That means closing for 24, maybe 36 hours."

Pumps keep the water circulating and clean. Without them, dirt would remain in the stagnant water. Preventive maintenance is the answer, says Sissler, who removed his pool's pump at the end of each summer and has it overhauled during the winter.

Managers must also be concerned about the parking lot, particularly when an ice cream vendor shows up and children stream into the lot to gretet him. Engley's solution to this potential safety hazard is to allow only one particular ice cream vendor to sell in a specified part of the pool parking lot at pre-arranged times each day. Even then, problems can arise.

"I had to ask the ice cream man to stop selling bubble gum," Engley said recenly. 'It was being spit out and sticking to people's feet and getting in the pool."

Despite their rules and precautions, things occasionally do go wrong for mangers.

Engley worked until 3 a.m. the morning the pool opened this summer trying to correct a malfunction in a valve that controlled the flow of the water to the pool. Several hours later, a bit bleary-eyed and dreary, Engley watched his pool open on time.

Then there was the time last year Engley and an assistant worked well into the morning hours unplugging rocks that were blocking a breather into a sewer line. Not the most pleasant experience, Engley admits, but "we did it so the pool could open on time the next day."

Such is the stuff super heroes are made of.