As development surges, Loudoun County and its towns are allowing more contractors and landscapers to use water from fire hydrants -- and, in turn, are losing more water and revenue to theft or improper hydrant use.

Purcellville officials, for example, estimate they will lose 750,000 gallons of water, worth $3,750, to theft -- a little more than the town produces on a midsummer's day -- and an untold amount in damages to the water system by the end of the year.

To stem the losses, jurisdictions are cracking down. Purcellville is fining violators and considering offering rewards to residents who report such crimes. Leesburg is adding warnings in Spanish to hydrant labels that caution against taking water without permission. And Loudoun County is unveiling a tightened permitting process for use of its hydrants.

"It's a pretty common problem," said John Cramer, superintendent of Leesburg's utility line division. "Some of the theft that we see is truly just an honest mistake, and some of it is just outright theft."

Most jurisdictions allow construction companies and landscapers to fill tank trucks with hydrant water. After getting a permit, these businesses rent a meter that must be hooked to a hydrant each time water is pumped, and the meter measures how much they take. To pay for the water, companies must periodically call in readings.

Company officials usually are shown a map of a jurisdiction's boundaries and told not to use the meter on hydrants outside that area. To be extra clear, jurisdictions mark their hydrants with signs denoting ownership, such as "Town of Purcellville."

Nevertheless, local officials say they are seeing a growing number of workers using meters from other jurisdictions -- a Loudoun meter hooked to a Leesburg hydrant, for example. When that happens, the jurisdiction that issued the meter might be overpaid, but the locality providing the water gets nothing, and that amounts to theft, officials say.

Officials say most theft is unintentional, made by workers unaware they have crossed jurisdictional lines or who do not read English. But some meters come from so far away that officials say they are sure workers know they are in the wrong place.

"When you've got a Prince William meter, you're 50 miles from the closest hydrant," said Purcellville Town Manager Robert W. Lohr Jr. "We don't buy that you ended up getting lost."

He speculated that some workers in the area, concerned about rising fuel costs, might simply decide it is not worth driving to a proper hydrant when they can use one nearby.

The problem is especially acute in Purcellville, which does not sell hydrant water. Eighteen times this year, the town has caught construction workers taking water from hydrants -- more than half of those cases in the past six weeks. The town has fined violators more than $10,000 in total.

Lohr said he thinks that represents less than 10 percent of total thefts and that he is less concerned about the loss of revenue than about the potential damage to the town's water system. Workers who shut hydrants improperly can cause a break in a water line, he said.

The town is developing a plan to reward residents who report improper hydrant use by discounting their water bills, Lohr said.

Leesburg paints its meters blue to make it easier to spot outside units, and officials regularly find workers using meters painted other colors, said Aref Etemadi, deputy director for the Leesburg utilities department. When that happens, officials confiscate the meter, read it and ask the issuing jurisdiction for the previous reading. The violator is required pay the difference, "in the hopes of maybe this will teach them a lesson," Etemadi said.

Purcellville does the same thing, then adds fines of as much as $1,500 to boot. Lohr said companies rarely commit the crime twice.

Soon, fewer Loudoun hydrants will be available for use by construction companies, said Samantha Villegas, a spokeswoman for the Loudoun County Sanitation Authority, which also fines violators. To get a meter, applicants will have to show proof of identification and business.

Now, she said, "folks sometimes come to us to get a permit and claim to be with a company, and they're not with that company. Then they're not calling in readings, and they're essentially stealing water."

Even with the strengthened measures, local officials acknowledge that water theft, like any crime, is impossible to stop completely. The key, they said, is making sure that workers know the rules and that residents report hydrant use that seems amiss.

"There's a lot of trust in the transaction," Villegas said. "We know that we're going to lose some."