The most common kinds of pipes used in homes are copper and galvanized iron.
Plastic piping also being used more and more. At present, copper is the most desirable material for piping because it is non-rust and does not build up scale, which can clog galvanized piping. Rust, which can occur in galvanized pipes, not only discolours and "tastes" water, but also can stain fixtures and clothing washed in it.
Because the water reaching your home is under pressure, you have only to turn on a tap and the pressure forces the water out. This pressure also ensures that the water can travel wherever it is needed, upstairs, around corners or whatever. All the water comes to your home as cold water. It is fed through pipes to all cold-water outlets and one part of the cold water system carries water to the water heater. From here, the hot water is carried to the required fixtures such as shower and kitchen sink.

Waste water system - Drainage.
Diagram (B)

The other part of the system is drainage to carry away used water and waste. This system is gravity operated, that is all the pipes go down hill, draining out of the house and into the sewer line. Drainage pipes are easy to tell apart from incoming water pipes because they are larger and heavier. Larger pipes are needed because the drainage system must be able to cope with large amount of water at any time, such as when many fixtures in the hose are being drained simultaneously.
Because the out going water is not under pressure it can simply run away, possibly living a vacuum in the pipes which would let sewer smells and gases into your home. To prevent this, your plumbing system provide vents (see Diagram (C)) usually open pipes which stick up from the roof of the house and allow air to enter the drain pipes, helping the waste water on its way more effectively. Every sink, tub and toilet in the house also has something called a trap built into it. These are the curved pipes you see under the sink. See Diagram (C). When the basin empties, water flows out with enough force to push it around the bends in the trap and out of the drain. Same water always remains in the trap, however, and this is by design - to seal the pipe against smell and sewer gas escaping into the house. Same plumbing fixtures such as toilet and baths have a trap built in. As well as providing a seal, these traps catch grease, hair and other rubbish where it can by caught and cleaned out.

Typical double chamber septic tank.
Diagram (C)

Waste disposal from the house travels through a main drain directly to the sewer line, septic tank or other disposal system. With most city sewerage, the waste is removed entirely from your property and chemically treated elsewhere. But if you have a septic tank, the waste is piped into a tank on your property. This tanks are subject to local health regulations and required cleaning of their accumulated waste from time to time to ensure they go on operating efficiently. The waste from the kitchen sink also passes through a "grease trap" which is usually a square concrete box sunk into the ground. It is usually situated near the kitchen so that the pipes can pass in and out from the septic tank. It also needs cleaning regularly.