Ted Carmack, of Bethel Park, thought he had done everything to secure the home of his elderly in-laws when they moved into assisted living last summer.

He locked the doors and windows of their two-story red-brick house near Grandview Park on Mount Washington, turned down the thermostat to 60 degrees and shut off the water.

Mr. Carmack, 70, a retired pipe fitter, and his wife, Mae, 66, who drove a school bus for the Bethel Park School District for 32 years, returned from an extended Florida vacation earlier this month. Although they made arrangements to have their mail forwarded while they were gone, not all of it was.

"It's better to have [a family member, friend or neighbor] look through it, forward the bills and anything that looks important, and set the other stuff aside until you return," Mr. Carmack said.

One of the pieces of mail waiting for them when they returned was a bill for $2,885.93 from the Pittsburgh Water & Sewer Authority. It said 107,000 gallons of water had been "used" from Dec. 21 to Feb. 3 at the former home of his in-laws. It said 146,000 gallons more had been used from Feb. 4 to March 3.

"I thought it was a mistake," Mr. Carmack said. "I personally shut off the water in that house."

Unfortunately, someone had entered the house and turned the water back on. That someone then opened the valve leading to the hot water tank and the faucet at the bottom of the tank. Although maintenance-minded homeowners do that at least once a year to clear sediment from the bottom of a water heater, the trespassers apparently just wanted to be jerks. Fortunately, the water flowed into a floor drain.

Mr. Carmack shut off the water at the meter, as he had done before, and removed the meter. He called the water authority and asked that the water be shut off at the front curb.

But what about the bill?

"The water authority wants 25 percent [$240] immediately and the balance over the next 24 months," he said. "We didn't know where to turn, so we decided to call you."

I called Julie Quigley, customer service manager for the Pittsburgh Water & Sewer Authority and explained the Carmacks' problem. She said she would call them.

"She was terrific, very helpful," Mr. Carmack said. "She suggested we call [the in-laws' insurance company] to see if their homeowner's policy might cover the cost."

Ms. Quigley said the authority sent the Carmacks a notification letter on Feb. 4 to alert them about "high water consumption" at the Mount Washington house. Unfortunately, they were in Florida and didn't receive it.

She said she arranged an "affordable" down payment and a payment plan for them. "All of our payment plans are interest-free," she added.

In addition to locking doors and windows, turning down the thermostat and shutting off the water, the authority advises those who are responsible for a vacant house to place lights on timing devices to turn them on and off at various times, including a light with a colored bulb that goes on -- and can be seen by neighbors -- if the interior temperature falls below 40 degrees; make regular visits, but not on the same day of the week or at the same time; and notify local police.

If you have a problem with the Pittsburgh Water & Sewer Authority, contact the authority at 412-255-2423, www.pgh2o.com and/or info@pgh2o.com.

Postscript: Mr. Carmack called Tuesday to report on a visit he and his wife made that afternoon to her parents' home. When they arrived, they found the rear storm door unlocked and the white kitchen door kicked in so hard that its frame was loose.

"We didn't go inside because there was a strong odor of gas," he said. "We drove down to the [Zone 3] police station on Warrington Avenue and explained what we found. Three officers came back with us and searched the house from top to bottom and then called the fire department. Three firemen arrived, shut off the gas, opened all the doors and windows and used a fan to clear out all the gas."

Mr. Carmack said the firefighters showed him where 30 to 40 feet of copper pipe had been removed in the basement. "I think these copper thieves are kids, stupid kids. They didn't shut off the gas before cutting the copper. They could have blown themselves up."

He said the police officers showed him a front window apparently used to enter the house by the vandals who turned on the water in late December. "The police officers and the firemen did a great job," he said. "We really appreciate their help."

He said he and his wife found a futon that had been opened, a pillow and a bedspread. "Nothing appeared to be stolen, but we took a TV and microwave. We're going to remove the main [electric] breakers and board up the house. It's a shame. My in-laws worked hard all their lives and this is what they get. It's just not right."