According to Wikipedia, Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water delivery are among the most common uses for plumbing, but it is not limited to these applications. The word derives from the Latin for lead, “plumbum,” as the first effective pipes used in the Roman era were lead pipes.

In the developed world, plumbing infrastructure is critical to public health and sanitation.

Boilermakers and pipe-fitters are not plumbers although they work with piping as part of their trade and their work can include some plumbing.

The 3 Types of Plumbing Systems

Every home has 3 basic types of plumbing systems. supply lines, fixtures, and drains.

Although it seems like a random jumble of pipes and fittings, this system works together in a logical way.

1. The Supply Line System

The first type of plumbing system is the water supply line. It provides your home or office with a continuous source of safe drinking water.

The main supply line is made up of pipes, fittings, and valves.

Water enters your property from a municipal water system or, in rural areas, from a private well.

How Does Water Get to You?

Water typically flows through a curb valve near the street.  You could also say that this portion of the supply system is owned by the city.  If your house has no basement, no crawl space, or is built on a slab, the water meter and shutoff valve should be located in a utility room or closet.

Potable Water Travels by Water Pressure

The force that pushes water to where it needs to go is called water pressure. The pressure should be just right for the plumbing not to leak or burst. If the water pressure in your area’s supply line is between 35 and 75 PSI, you should be OK for an average A good water pressure should be in the range of 40 to 60 PSI (50 PSI is the best for most households). If your pressure is less than ideal, you may not have enough water flow. In order to reduce the risk of bursting pipes, you must ensure the water pressure is not too high.

Cold & Hot Water Runs

From the cold water main line one pipe splits off to branch into the supply pipes for the water heater and the hot water.

Secondary lines are used to distribute water around the building and may consist of small pipes with or without a main pipe.

A well-designed piping system should have valves installed at each main junction.

A flow control valve is the perfect device for anyone who needs to turn off the water to a fixture without shutting off water from the rest of the house.

2. The Plumbing Fixtures System

A fixture is the second of three types of plumbing systems in your home. A toilet or water closet is a fixture. Includes everything from sinks, to bathtubs, to showers, to toilets, to sprinkler systems, and to water using appliances like dishwashers and clothes

These fixtures are part of a temporary or permanent connection between the supply and drainage systems.

There are other fixtures in which a single fixture does not use both a hot and cold water line.

What are Air Chambers?

Fixtures in most buildings have a column of air inside the walls, or behind the wall.

This column of air is considered an air-chamber is used to prevent a quick and sudden release of air pressure and thereby to protect the water supply system. If the system became damaged, this could cause a bursting pipe or fittings that could result in a water hammer. This causes problems like damage to pipes and fittings.

3. The Drain-Waste-Vent (DWV) System

The third basic type of plumbing system is the drain system.

Home plumbing systems are often referred to as the DWV, or drain-waste-vent system.  The fact that it is the most regulated by plumbing and housing codes has good reason. It’s also the most strictly regulated type of system.

Wastewater Travels by Gravity

Drainage doesn’t have a pressure-type water system, like water supply systems do. It relies on gravity to carry waste out of the house.

P-Traps Are Your Friend

All fixtures in the home are connected to drains by P or S traps (though S traps are now considered illegal according to the U.S. Uniform Plumbing Code). Each trap is full of water to prevent sewer gas from entering your home. A toilet works by forcing water into the sewer. The water pushes any solid matter (like garbage) through the drain, where it’s either sent out to the sewer or a treatment plant

Wastewater can go out, but due to the water trap, small animals and sewer gas can’t get in. When we flush or drain a sink, the water in the trap is replaced.

Stacks & Venting

Branch drains lead to a larger vertical pipe called a stack. The bottom of the vertical stack is at the same level as the outgoing sewer line. Your stack goes all the way up to your roof and vents air out of your system.

A larger home has multiple stacks that make a near-45-degree turn to become the horizontal main sewage drain. It slants down away from your house (this downward slope takes advantage of gravity to move wastewater) and enters a public sewer line or private septic system.