As Harold Stearn puts it, he and his men - who maintain the city's labyrinth of water and sewer pipes - are invisible to the ordinary District resident until something goes wrong.

Well, a lot has been going wrong during the last 10 days, and many residents have seen Stearn's men. They were the men with the propane torches from the city's Department of Environmental Services who answered the frantic calls from citizens to unfreeze water meters or turn off the water when pipes broke in the subfreezing temperatures.

An average of 175 telephone calls per day for help have been pouring into the water division, headed by Stearn, since the temperatures started plummeting to record and near-record lows earlier this month.

To meet the additional demand, 20 to 25 extra two-man crews worked through last weekend. This compares to the one three-man emergency crew that is usually on duty, Stearn said.

"We have quite a few employees where 16-hour days were normal, and some have worked 24 hours," he said. With the current warm-up in tempeatures, Stearn reduced the number of extra crews to two by last night.

The water division has had more calls for broken or frozen pipes on each of the past 10 days than it had in all the last five years put together, Stearn said, "because we've had very warm winters."

Stearn's men unfreeze water meters only and not the rest of the line from the water main in the street to the home because the line is considered the property owners' responsibility, Stearn said.

To stop water from pouring into a residence because of a broken or damaged pipe, a water division crew turns off the water to a home. Stearn said he has discovered during this cold spell that "the average homeowner doesn't know to turn off their water."

The water meter is susceptible to freezing because it is located only about 18 inches from ground surface, Stearn explained.

"We've even resorted to building minor fires with a gasoline rag or wood" to thaw a water meter, Stearn said, admitting this is "risky" because of the possibility of a leak from nearby gas pipe.

Stearn advised homeowners to keep their water running at a tirckle if they fear frozen or broken pipes but added, "if you leave the tap open please don't leave home."

Citizens in trouble can reach Stearn and his men by calling 462-4430 or the city's command center at 629-5151.