Polyvinyl chloride (PVC) pipe is strong, durable and easy to work with, and it is commonly used in home plumbing systems. These qualities may make PVC pipe seem like a good choice for venting a clothes dryer, but the opposite is actually true. For a variety of reasons, PVC pipe is not recommended for use in dryer vents, and it can actually be ineffective and dangerous.
A number of deposits accumulate naturally inside water heaters, including iron and calcium. Calcium deposits are carried into the tank with the incoming cold water. These deposits collect in the bottom of the tank and will gradually reduce the efficiency of the unit. To prevent this, water heaters are fitted with a flushing valve located on the side of the bottom of the heater. The valve accommodates a garden hose, which you can use to quickly evacuate the deposits.