Rossen Reports: Hidden camera investigation -- plumbers If you're calling a plumber, chances are you have an emergency. In need of quick help, you trust them to fix the problem at a fair price. NBC's Jeff Rossen uses hidden cameras to investigate which plumbers get it right and who lands in hot water. By Jeff Rossen and Josh Davis, TODAY If you're calling a plumber, chances are you have an emergency; you're desperate, in need of quick help. You trust them to find the problem and fix it, at a fair price. With our hidden cameras, we tested plumbers to see who gets it right -- and who lands in hot water. We rented a house in New Jersey, home to Liz, a mother of four. Down in the basement, she had a hot water heater in good shape. We know, because we had three experts, all licensed master plumbers, inspect it from top to bottom. One of the experts was Pete Voros, chairman of New Jersey's state board of examiners of master plumbers, who has been in the business for over 30 years. Voros set up a simple problem with the heater, turning a screw just a hair to start a small leak from a valve, creating a puddle on the floor. The fix? Easy! Just tighten the screw -- something he said any plumber should spot in a minute. We wired the house with hidden cameras, covering every angle. Then we had our mom call 10 plumbing companies to come over and diagnose the leak. As each company showed up, we were watching with our expert from a control room upstairs. Things started off great. Within a minute, the first plumber found and fixed the problem -- that easy turn of the screw. "The drain valve was just slightly open, just a hair," he told Liz. I just closed it. And he refused to charge for it. Amazing! And the next few plumbers also fixed the problem in just minutes. But then our luck went down the drain with a plumber named Frank. Rossen Reports: Do chimney techs charge you unnecessarily? He checked the tank and found and fixed the leak. Turning that screw -- problem solved! But he told our mom it was still dripping: "The water heater has to be drained, and then you need a new valve put on." And that will fix the leak? Liz asked. That'll fix the leak. That's right: Even though he fixed the leak, he still wanted to put in a brand new valve. Price: $359. "What do you make of that?" we asked Pete Voros. "I think he's trying to take advantage of the homeowner, financially," Voros said. We had some questions for Frank. "You tightened the screw and it stopped leaking, right?" we pointed out. So why are you replacing the valve? It was still forming a drip. Actually, the drip had stopped. But he said he didn't want to hang around and make sure. Or have to come back. If you think he was pricey, the next plumber took it to another level. Just seconds in, he saw major problems. "There's no fixing it except for replacing it," he said. You'll get a brand new unit. The cost: A whopping $1,675. "The leak was coming from this valve," we pointed out. Did you even check this? "I didn't see nothing here," he said. Didn't see? Our expert said it was dripping right in front of him. He couldn't explain that and decided to leave. We reached out to the company owner, but didn't hear back. Rossen Reports: Family discovers their tap water is flammable But the biggest bill was still to come. A plumber named Joe spent a lot of time looking, touching, and staring at the heater. At first he said, "I think it's coming from here." But minutes later, he changed his tune, saying, "Replace it. Take this one out. Put a new one in ... I'll do it for 1,900 bucks. Nearly $2,000 to replace a water heater our expert said could easily last another 10 to 15 years. "Why do you want to charge her $1,900?" we asked him. "Because I told her the bottom of the water heater is leaking," Joe said. It feels like the bottom is wet. But our expert said all that was really wet was his explanation. "Experts say this hot water heater is working perfectly," we told him. "OK then, they they're right," he retorted, slamming his truck's door. In the end, most of the plumbers did the right thing. But, our expert said, nearly half tried to charge Liz big money for work she didn't need. Experts say, before you get any work done on a pricey appliance like a hot water heater, you should get three estimates. It's also a good idea to ask friends for a recommendation instead of randomly searching for a plumber online. And definitely call your local consumer affairs office to make sure the plumber is licensed.