ROCKY HILL, Conn. -- Do you ever wonder what's in the water coming from your tap?

Southington resident Cheryl Santaw said she walks by the water tower in her neighborhood all the time and wonders what it looks like on the inside.

"Sure, I wonder," she said.

During an investigation into water stored in water tanks, the Channel 3 I-Team inquired about a number of water tank inspections in the state.

Many of the systems the I-Team looked at have full internal exams done on a frequent basis, sometimes every five years.

Under current state guidelines, the tanks should be checked once a decade, but there's no law requiring that it be done.

But the Middletown Water Department follows the guideline. A half-million-dollar-plus upgrade is taking place on one of the town's tanks, said Guy Russo, the department's director.

"It's a full structural repair of the tank," he said. "Along with a sand-blasting and painting, plus some enhancements for mixing water in the tank, this is bigger than most."

Officials said water departments determine what needs to be done by conducting tank inspections. The inspections are done one of two ways: Either a scuba diver can go in with an underwater camera, like they do in Manchester, or a remotely operated vehicle can do the same thing, scanning for structural problems, excessive debris and other issues.

Ted Lund owns and runs a company called Extech LLC out of Deep River. He said his company uses robotic vehicles to assess and clean tanks all over the country.

Lund said some unwanted stuff can be found during searches, such as animals that can get in through poorly maintained screens.

"In every state, we have seen examples of dead birds in tanks, dead squirrels in tanks," Lund said.

He said he hasn't seen an instance of that lately in Connecticut. Usually what's found is a layer of sediment on the bottoms of tanks that looks troublesome, he said, but's usually harmless.

"For us, an inch of sediment, you know, we've found to be quite common," Russo said.

There's also bacteria-killing chlorine in the water, officials said, which is tested often.

"We pull samples from faucets from where people take their drinking water and that's analyzed at the lab every week," Russo said.

Officials in Manchester, Bristol and Waterbury said they have similar practices.

While the water tested in Waterbury showed no signs of problems, the I-Team found that the Brass City's Bureau of Water didn't have documentation to support that all the water tanks are being internally inspected within a 10-year window as recommended by the state.

"Everything's fallen within the regulatory requirement," Russo said.

But when asked if all of the tanks have been completely inspected, he said, "I'm not sure every one of them has. We've done the sanitary survey and maintenance inspections."

Two years from now, water suppliers will have it a bit tougher. That's when this guideline that tanks get checked every 10 years becomes a state regulation and will be enforced.