What Is Plumbing?

Plumbing is the system of pipes that supply drinking water, drain sewage, and remove waste from homes and commercial buildings. It involves intricate construction that adheres to strict regulations.

Plumbers interpret blueprints and building codes to plan and execute new installations or repairs. They also maintain existing pipes, which can be made from a variety of materials. For more information, click the Holmes Plumbing and Drain to proceed.


Pipes are tubular sections, generally circular but not always, that convey substances which can flow — liquids and gases (fluids), slurries or masses of small solids. Pipes are made of a wide variety of materials, including ceramic, glass, fiberglass, many metals and concrete. Metal pipe is commonly constructed with welded joints. Pipes are standardized for dimensions and industry-type; pipe for residential construction falls under different codes than pipe used at power or chemical plants, for example.

There are seven main types of pipes found in the average home:

Copper pipes are a durable and efficient choice for water supply lines. They’re also easy to work with, especially when the pipe is bent, thanks to their flexible material. They are typically color-coded for easy identification.

PVC, or polyvinyl chloride, pipes are a versatile option for home plumbing. They can be used indoors and outdoors, and are great for drain and vent piping. They’re inexpensive, but they can be hard to install and may leak if not properly maintained.

PEX, or cross-linked polyethylene, pipes are a more recent innovation in plumbing. They’re flexible and durable, but they cost more than copper pipes. They’re also more resistant to rust and corrosion.

Pipes can be joined by welding, threading or using mechanical couplings. They can be sealed with pipe joint lubricant, PTFE thread seal tape, a PTFE bellows or a pipe donut. They can be buried underground, but they must have push-on gaskets that allow for lateral movement and expansion/contraction due to temperature changes. They can also be welded to a rebar for support and stability. Piping is a very specialized field, and unless a person has extensive experience in the industry, it’s not always intuitive to understand the nuances of the product.


Pipes establish the runs that bring in or take away water, but they’re nothing without the fittings to control their movement and manipulate the flow. Plumbing fittings come in a variety of forms from elbows to caps and serve to change the direction of the pipe, adjust its diameter, or connect different components. Some types of fittings are designed to be permanent, while others can be removed and replaced at any time to allow for inspection and repairs.

The most common and versatile pipe fittings are tees, couplings, and unions. These are available in various materials including copper, steel, CPVC, malleable iron, and PVC. Their designs vary to meet the needs of specific piping and plumbing systems. The bodies of these fittings are typically made from the same base material as the pipe to which they’re connecting, and the connections are threaded for a secure fit.

Elbows are used to change the angle of a pipe run, and they’re most commonly found in 90 degree and 45 degree angles. These are also offered in varying sweeps, which refers to the speed at which the fitting changes direction.

Tees are the most common and versatile plumbing fitting, combining or dividing water flow and transporting two-fluid mixtures. These are offered in a range of sizes and can be equal or unequal in size between their three outlets.

Couplings join straight lengths of pipes together and are available in a variety of styles and dimensional sizes to match the needs of a given system. These may be joined by solvent welding, soldering, or gluing. They’re also offered in a variety of materials such as brass, copper, CPVC, or steel, and they’re sometimes designed for special needs like fire resistance, earthquake safety, mechanical ruggedness, or theft resistance.


The term “fixtures” refers to the devices connected to the plumbing system that perform specific functions related to water supply and waste disposal. These include sinks, toilets, bathtubs, showers, faucets, urinals, and drinking fountains. Fixtures are available in a wide range of styles and designs to suit different needs and aesthetic preferences. In order to ensure that they are safe and effective, all plumbing fixtures must meet strict code requirements.

For example, all fixtures must be installed at a minimum distance from finished walls and other plumbing, and they must have smooth, impervious surfaces that are free of defects. Additionally, most fixtures must be constructed from durable materials that can withstand the rigours of daily use and frequent cleaning. Finally, all fixtures must be properly installed in accordance with the manufacturer’s rough-in sheet and instructions.

Every fixture is equipped with a water supply line for delivering water and a drain or waste pipe for disposing of wastewater. In addition, some fixtures are fitted with additional components to support their function. For example, kitchen sinks typically have a garbage disposal unit to dispose of food waste. Similarly, bathtubs often have jets or a shower head for washing or bathing.

A drain trap is a special type of plumbing fixture that provides a seal between the waste and supply pipes. The trap prevents sewage and other contaminants from entering the freshwater supply. It also helps maintain a positive pressure in the waste pipes, which prevents water from flowing back into the freshwater supply. The seal in a drain trap can be lost due to siphonage (direct or indirect, momentum, capillary attraction, or wind effect), backpressure, evaporation, or improper installation.


A sewer is a pipe that conveys anything classified as waste or grey water from a home or business to a municipal wastewater system or a private sewage treatment system like a septic system. The main difference between a drain and a sewer is that a drain serves only one building, while a sewer line serves an entire municipality or township.

For cities and towns, the sewer lines are usually owned by the local government. The pipes are complex networks that collect sewage, water runoff and stormwater and transport it to a wastewater treatment plant or disposal point. The city or town’s sewer system consists of collection pipes, manholes, lift stations, pumps, screens and flow meters.

The sewage and waste water are typically transported in a gravity fed system from homes and businesses to the wastewater treatment plants by means of an underground network of pipes. These pipes are typically made of vitrified clay, asbestos cement or reinforced concrete; the larger sewerage systems use steel, cast iron and ductile iron for the force mains.

It’s important to note that the water and sewage on your utility bill are two separate charges. Water is billed by the gallon, and sewage is charged by the amount of waste that flows down your drains into the sewer. Understanding the difference between these two services will help you understand your plumbing bill better and how to save on your sewage and water consumption. A state licensed plumber can assist you in reducing your water and sewage bills. Using a little preventative maintenance and taking advantage of available water conservation tips can really go a long way to cutting your sewage costs.

Force Mains

Sewer force mains are pressurized pipes used to pump wastewater uphill. They’re designed for regions where the topography can’t support a gravity sewer system and help transport wastewater from low-lying areas to treatment plants or other destinations. Like other sanitary sewer line systems, they use pumps to create pressure and are built from a variety of materials.

The lifespan of a sewer force main depends on several factors, including material selection, site conditions, and environment. For example, a sewer force main that discharges into a highly saline water table may be prone to corrosion. In this case, an inert pipe such as HDPE or PVC might be more suitable due to their corrosion resistance.

Another factor that contributes to a force main’s longevity is its ability to handle the pressure of pumping and the corrosive nature of sewage. In order to meet these demands, ductile and cast iron piping is often selected as they offer high strength, larger inside diameters, tight joints, and resistance to corrosion. Additionally, thermoplastic piping is sometimes used in force mains, as it offers less weight, lower hydraulic friction, and resistance to corrosion and microbial attack.

Though they only make up a small percentage of the total length of a wastewater system, failures on these critical pipelines can have serious health, environmental, and financial impacts. The good news is that most force main failures are preventable. By deploying new technologies to assess and inspect sewer lines, utilities can dramatically reduce the frequency of high-consequence failures, lower maintenance costs, and improve overall system performance. This is accomplished by leveraging actionable information to target problem areas and address localized threats, rather than relying on traditional inspection methods that are time-consuming, labor intensive, and inaccurate.