Plumbing systems are complex networks that transport both water and waste. Plumbers design, install, and repair these vital systems. They interpret blueprints and building codes, make repairs, and ensure all components meet local safety and health standards.
Learn the basics of plumbing systems, including their water supply lines, drainage pipes, and venting system. Also, discover the different types of pipes used in residential settings — from PVC and copper to cast iron and more — each with its own benefits and drawbacks. Click Here for more information.
Water Supply
The water supply line brings fresh, potable water from a public water system or private well into your home or building. From there, it connects to plumbing fixtures that allow you to use the water for drinking, cooking, washing, and bathing. Water supply lines are typically made of copper or a durable plastic, such as PVC or PEX. The pipes must be large enough to accommodate the water pressure and flow required by your household. They must also be insulated to reduce the risk of freezing in cold climates.
The system includes a main water shutoff valve, which must be kept in good working order to prevent accidental water loss and to enable emergency plumbing repairs when needed. It is also common to have a water meter installed to record the water usage for billing purposes. Water supply lines may also be connected to a water heater, which heats the water for consumption or space heating.
While you probably think of your home or building’s sinks, toilets, and showers when you think of plumbing, the water supply line is actually the most important part of your plumbing system. Without a functional water supply line, none of your plumbing fixtures would be able to function.
In addition to bringing in fresh, clean water, your plumbing system is also responsible for carrying waste water and storm runoff away from your building. The drainage system, which consists of pipes, traps, and drains, is vital for ensuring that waste and water don’t build up and cause flooding or health issues.
Depending on the size and complexity of your plumbing system, you may have different types of pipes for your water supply and drainage systems. Copper pipes are popular for water supply lines because they’re durable and resistant to corrosion. Other pipes, such as PVC and PEX, are commonly used for drain lines because they’re affordable, easy to install, and resistant to blockages. Stainless steel pipes are also available for plumbing supply lines, which offer a combination of durability and resistance to corrosion and extreme temperatures. The type of pipe you choose should depend on the environment where it will be installed and the amount of water you consume.
Drainage
The drainage to your plumbing system whisks wastewater away from household fixtures, bringing it to the sewer line or septic tank. This essential service helps prevent flooding, mildew and rotting in residential areas, as well as sanitary health problems. It’s a vital part of every home, and like all parts of the plumbing system, it needs to be properly maintained.
The drain-waste-vent (DWV) system, or sanitary plumbing system, includes all the pipes in your home that carry water and waste away from sinks, bathtubs, showers, washing machines and toilets. It’s also what connects these devices to your house sewer line or septic tank, or to the public water supply. The DWV system is the least visible part of your plumbing, but it’s the most critical for keeping your home healthy and functioning.
These pipes are angled downward to allow gravity to help move water through the system and toward the drain trap. In most homes, the piping is made of copper, steel or plastic tubing, although older houses may have lead pipes. Regardless of the material, the piping should be sized appropriately to avoid clogs or other problems.
A key part of the sanitary plumbing system is the drain trap, a U- or P-shaped section of pipe that stays full of water to prevent the backflow of wastewater and sewer gases into the house. The trap is connected to each drain, and each fixture should have a drain cover that helps seal the trap when it’s not in use.
Since the sanitary plumbing system is directly connected to the sewer line, it’s important that residents and business owners take care not to put anything down the drains that could clog or block the lines. This includes non-biodegradable items, such as plastic products, that are marketed as “flushable,” as well as fats and oils.
Regularly pouring boiling water down the drains can help dissolve soap scum, grease and other buildups that can clog the pipes. It’s also a good idea to have your sewage system regularly inspected, especially after heavy rains. Your plumber can check for any clogs, breaks or other issues before they become serious.
Vent
The plumbing system needs two important components to work together to supply water and remove waste: the drainage pipes and the vent pipes. While the drainage pipes carry water and sewage away from the home, the vent pipes provide the air movement needed for the drains to move the waste properly.
Without a functioning vent system, wastewater would create a vacuum inside the drainage pipes that could prevent water from flowing. A vent pipe allows fresh air to enter the drain pipes and neutralize the negative pressure, allowing water to flow freely. It also provides a way for sewer gases (which contain harmful compounds such as methane, hydrogen sulfide, nitrogen oxides, and sulphur dioxide) to escape.
A plumbing vent works with a drain trap or “P-trap” or “S-trap” that is installed beneath every fixture that drains into the main plumbing stack, such as toilets and sinks. A P-trap or S-trap seals the bottom of the drain with a layer of water to ensure that sewer gasses are forced up the vent instead of entering the house.
Each drain also has a vent pipe that connects to the main plumbing stack. These vent pipes extend through the roof, bringing fresh air into the plumbing system and maintaining proper atmospheric pressure in the drainpipes to allow wastewater to flow easily.
When a vent pipe becomes clogged, the result is that drains may not flow and foul odors will fill the house. A plumber can usually clear the clog with an auger, but it is important to regularly check the condition of the vent stack to make sure it’s unobstructed.
If you’ve noticed slow-draining drains or a gurgling sound when a bathroom or kitchen sink is in use, it’s probably time to have the vent stack inspected. If you have a wet vent, make sure it isn’t obstructed by leaves, birds’ nests, or other debris. In cold climates, a vent pipe can freeze and block the airflow, so it’s important to insulate it. The ductwork should be sized to accommodate the water and sewage load of the plumbing system, as well as local weather conditions.
Septic System
While many people take for granted the drainage system that disappears every time they flush a toilet or wash their hands, few consider the machinery behind it. There are two major ways homes and commercial buildings get rid of wastewater: sewer systems and septic systems. Sewer systems are more common because they’re funded and maintained by local governments, but septic systems have grown in popularity as an environmentally sound alternative that gives homeowners full control of their drainage system.
The septic system starts with a pipe that leads from each drain in the home to the septic tank. The tank itself comes in a variety of sizes and configurations, and your local service professionals will help you choose the right one for your home. Inside, the septic tank separates wastewater into three layers. Everything that floats rises to the top, creating the scum layer; everything that’s too heavy sinks to the bottom, forming the sludge layer. The wastewater in the middle is a clear liquid that flows out to the absorption field.
As wastewater moves through the septic tank, bacteria digest it. This produces gases, including hydrogen sulfide, which smells like rotten eggs. To avoid a buildup of pressure that could block or reverse the flow of wastewater, these gases are vented to the air through a pipe in the tank lid. The vent should be located a reasonable distance from any other plumbing fixture, and it should be fitted with a charcoal filter to reduce odors.
Wastewater flows from the septic tank through a pipe that leads to the leach field, or drain field, where it is treated by the soil. The leach field consists of a network of perforated pipes, or soakers, that are buried in the soil and allow treated wastewater to seep through the ground.
As with any part of a plumbing system, the leach field needs to be properly maintained. It should be kept free of debris, and trees and other plants should be avoided near the absorption field because their roots can clog pipes. It’s also important to check the leach field regularly and have it pumped when necessary.