Even as New Jersey declared a drought warning Friday for 14 northern counties, Carmen Tierno was in good spirits as he strolled past the holding tanks, "pulsators," chlorinators, generators, and "atomic absorption lab" where he works.

The southern end of the state is not feeling the impact of the long dry spell that has shrunk reservoirs and lowered groundwater across some other parts of New Jersey, said Tierno, a senior director of operations for New Jersey American Water company.

"We're relatively water-rich," he said, thanks in part to the giant water treatment plant he oversees in Delran. It draws and purifies 25 million gallons from the Delaware River every day.

Notwithstanding the plant's mighty capacity, however, the New Jersey Department of Environmental Protection issued a drought watch on Oct. 5 for Burlington, Camden, Gloucester and Salem Counties and urged homeowners and business to engage in voluntary water conservation.

Precipitation in the four counties this year has been rated moderately dry, according to the DEP, while stream flows and groundwater are rated severely dry, one step below the "extremely dry" conditions that much of upstate is experiencing.

On Friday, following a public hearing in Essex County that said some upstate reservoirs are at half-capacity, the DEP issued its drought warning for Bergen, Essex, Hudson, Hunterdon, Mercer, Middlesex, Monmouth, Morris, Ocean, Passaic, Somerset, Sussex, Union, and Warren Counties, an area with 7 million residents.

That declaration, which encourages voluntary conservation, gives the DEP legal authority to direct water to areas most in need and restrict flows from reservoirs.

As conditions worsened, that warning escalated to "emergency" status, which lasted to early 2003 in some parts of the state.

Those restrictions barred most lawn and shrub watering, car washing, hosing of driveways and sidewalks, sewer flushing, power washing, and even restaurants serving water unless requested.

As he showed the workings of the Delran plant, Tierno urged the 110,000 households and business served by New Jersey American's southwest operating area to engage in voluntary conservation.

"But from an operational point of view we're not feeling the impact" of the reduced rainfall, Tierno said.

In addition to its Delaware River Regional Water Treatment Plant, which began operations in Delran 20 years ago, New Jersey American's southwest operating area draws another 25 million gallons a day from 70 deep wells and 37 other facilities in the four counties.

Northern counties rely much more on reservoirs, he said, which are subject to evaporation.

Tierno is operations director for New Jersey American's southwest network, which extends from Mansfield in Burlington County to Carney's Point in Salem County.

At the plant he pointed out the glass-walled control room that serves as operations center for the network.

"See that guy there?" he said, pointing to a man sitting at a computer beneath three giant screens.

"With a click of a button he can move water wherever it's needed" in the network, Tierno said. Its numerous pump stations, he said, can direct water supply around any breaks in the system.

Using charts, opening doors, or pointing through windows, he showed how intake pipes in the Delaware off Taylor's Lane first send river water to a 15 million-gallon outdoor pool where some of the natural greenish-brown solids settle.

The water is then piped through a series of tanks and devices that aerate it, remove more solids, oxidize it, neutralize its pathogens with ozone or chlorine, and finally filter it through charcoal "polishers" before eight massive pumps send it across the four counties via 65 miles of transmission lines - some of them 54 inches wide - and 1,800 miles of street mains.

The average residence uses 6,500 gallons of water and pays $50 for it, Tierno said. "That's less than a penny a gallon."