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How Do Household Drain Systems Work?

Now is the time to understand your drainage system, not when our drain pipes have failed and are spilling dirty water into the house. When it functions properly, we don’t give much thought to all the distinct components of a residential drainpipe system. However, when it doesn’t function as it should, you should be able to identify the components very quickly.

Although we generally consider this system simply as the ‘drain pipes,’ to be officially correct, this system is called the DWV system-the Drain Waste Vent. It ideally outlines that the pipe system is not just designed to drain solid wastes and wastewater to the municipal septic field or sewer but also functions as a vent system allowing fresh air into our drainage system.

If you want to understand how your household drain system operates, here is everything you should know.

What is a residential drainage system?

A residential drainage system represents an extensive network of pipes, usually from gutters, downpipes, and the pipelines within your home. Invented by the Romans, it connects to your drainage system that spans cities and towns.

Residential drainage systems ensure that rainwater and household waste go to the sewer directly. Ideally, you should ensure that your drainage system is not only complete but also functional since improper installation can lead to damaged roofs, leaks, mold and mildew growth, and flooding.

How does it work?

The residential plumbing system comprises two specific subsystems. One subsystem directs fresh water to your house, and the other takes the wastewater out. Typically, the water that comes into your homestead is usually under pressure.

However, drainage systems don’t usually operate on pressure like supply systems. Instead, the waste matter leaves your premises because all the drainage pipes angle, pitch, downwards towards the sewer. The waste moves through gravity pull, with the sewer lines continuing downwards, flowing to a septic tank or sewage treatment facility.

Although the drainage system sounds simple, there’s much more, including traps, vents, and cleanouts. Air enters the drainpipes through the vents sticking up your home’s roof. If there’s no air supply from vents, wastewater won’t flow out properly, and the water within the traps needs to be siphoned away.

What are the components that make a residential drainage system?

A residential drainage system comprises various components, including:

Stormwater Drainage System

Rainwater, if not properly directed to your neighbourhood’s central drainage system, can result in serious issues. Your home’s drainage system should contain provisions from rainwater. A functional rainwater collection system allows you to use the collected water for watering your landscape and lawn and cleaning. You may subsequently direct the stormwater to your town’s main lines.

Gutter Systems: The gutter system is the initial defence line of your house against the stormwater onslaught, and it plays an essential role in your house’s drainage system. The gutter’s function is to divert rainwater away from your premises and your home surrounding, like your driveway and lawns.

The gutter system safeguards your home’s foundation and landscaping, protects your driveways and concrete paths, and prevents basement flooding. Without the gutters, your rainwater to go somewhere, and without any structures to halt it, it can go to any part of your house. This is why it is essential to have it correctly installed and maintained.

Downpipes: From your home’s gutter system, the downpipes direct the rainwater down to a given place in the ground. The water can be directed to your rainwater collection system or move directly to your town’s primary underground drainage system.

The amount of stormwater in your locality can influence your home’s gutter specifications. Like gutters, downpipes direct rainwater away from your premises and towards your city’s central rainwater system. The downpipes feature accessories like joiners, offsets, and brackets and come in different sizes as per your needs.

Sewer Drainage System

Your residential water wastes must be appropriately directed to the town’s main sewer line since, if not correctly disposed of, it can result in unspeakable damage to your premises and pose serious health concerns.

Essentially, the sewer drainage system comprises underground pipes transporting water waste from your kitchen, bathroom, laundry, and other house plumbing fixtures. It moves sewage from your house to the main sewage system. Ideally, these water wastes go to the city’s treatment facility, where organic matter and rubbish are removed. The treatment facilities may subsequently use a unique process to recycle the water or direct the water treated to the nearest river or creek.

how household sewage system work (infographic)Your home’s sewer drainage system must include the following components:

  • P-Traps are situated beneath your bathtubs, sinks, and other plumbing accessories. P-traps are curved sections of your piping shaped like the letter P and hold the standing water preventing sewer gases from rising from the sewer system and smelling within your home.
  • Toilet Traps: serve the same function as P-traps and is a curved drain holding standing water and preventing the rise of sewer gases.
  • Clothes Washer Stand Pipe is a pipe connected to your home’s washing machine. Your washing machine’s drain tube empties into an exposed standpipe resulting in a branch drain into the house’s main drain.
  • Branch Drain Lines: These lines connect your house plumbing fixtures to your main drain lines. These lines are often hidden in your walls, ceiling, and floors.
  • Soil Stack & Soil Stack Vent: these vents are also called main drain stacks and are vertical pipes boasting large diameters. Soil stack vents are located in the upper section of the standing soil stacks and offer to vent to your sewer system. Stack vents are designed to carry toxic fumes away and facilitate the release of pressure to allow your wastewater to move downward freely.
  • Main Drain Line: This pipe connects the residential sewer system to the municipal’s main sewer system. It runs beneath your home’s slab foundation.

What Are The Most Common Drainage Problems?

Most common home drainage issues are easy to identify and prevent before they become massive repair concerns. Some of the most familiar drainage problems you should look out for include:

  • Sluggish or clogged drains: when your drainage is clogged, sluggish, or begins to emit foul smells, you should immediately unclog it to avoid massive problems.
  • Downpipe issues: where your downspouts can’t handle all the stormwater, this results in pressure on your home’s foundation or flooding your basement. It would be best if you relieved the pressure by installing gutter extensions to various ideal garden areas by hiring professional drainage companies.
  • Overflowing gutters: You should instantly clean them where your gutters are overflowing. However, if your gutters are clean and clear, overflowing gutter problems can be due to undersized gutters, cracks, or dislocated gutter pipes that require professional plumbing assistance. Gutters gradually become the home for small animals and fallen leaves if not correctly maintained.


Familiarizing yourself with your residential drainage system and its main components can be vital, primarily when it is not functioning correctly. Understanding your home’s plumbing system can significantly minimize or entirely avoid most water-related problems.

Nonetheless, if you identify severe clogged and blocked residential drains, you can always consult a professional plumbing service to clear your blocked drains properly.

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