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Understanding Stormwater Drainage Systems: Importance, Differences, Maintenance, and Signs of Issues

Stormwater, a combination of rainwater, soil fertilizers, organic matter, and debris, is generated by rain runoff from various structures such as roofs and roads. As it flows down impervious surfaces, stormwater accumulates pollutants, necessitating proper management. A stormwater drainage system is designed to carry this runoff away from properties, preventing issues like flooding and water damage. This article explores the distinctions between stormwater and sewer drains, emphasizes the significance of well-maintained stormwater drains, and provides insights into effective maintenance practices.

Stormwater Drains Vs. Sewer Drains:

Sewer Drainage:

Sewer systems are designed to handle wastewater from households, businesses, and industries. This includes water from sinks, showers, toilets, and industrial processes. Sewage undergoes treatment at wastewater treatment plants before being discharged into bodies of water or reused for irrigation.

Stormwater Drain:

In contrast, stormwater drains are specifically built to collect rainwater runoff from streets, parking lots, and other impermeable surfaces. Unlike sewer systems, stormwater drains do not typically receive treatment. Instead, they channel runoff directly into rivers, lakes, or oceans. This means that any pollutants picked up by the stormwater are also carried into natural water bodies.


Sewer Drainage

Stormwater Drainage


Transports wastewater and sewage

Carries rainwater runoff

Materials Transported

Wastewater, toilet waste, food scraps, grease

Rainwater, leaves, twigs, soil particles

Discharge Location

Treatment plants before release into oceans/rivers

Directly into waterways (untreated)

Treatment Involved

Yes, wastewater undergoes treatment

No, stormwater is released untreated

Importance of Stormwater Drains

A functional stormwater drainage system safeguards properties from various problems. Here's how:

Minimal Flooding

By facilitating efficient water flow and preventing stagnant water accumulation, stormwater drains minimize the risk of flooding. Flooded streets become impassable, disrupting transportation networks. Overflowing waterways can damage infrastructure like bridges and power lines, leading to power outages and economic losses. In severe cases, flooding can cause basements to flood, leading to mould growth, furniture damage, and potential health risks.

Protection Against Stormwater Damage

Well-maintained drains ensure stormwater is diverted away from footpaths, basements, pipes, roads, and buildings, protecting them from potential damage. Unchecked stormwater can cause basement flooding, leading to ruined furniture, appliances, and stored belongings. The pressure of built-up water can cause cracks in foundations, compromising the structural integrity of buildings. Standing water around structures can lead to erosion, weakening foundations and potentially damaging walkways, driveways, and patios.

Reduced Water Contaminants

Clear storm drains help prevent pollutants from entering waterways. This safeguards the quality of our water sources. Stormwater runoff often carries pollutants like oil, fertilizers, pesticides, and sediment. When these pollutants enter waterways without treatment, they can harm aquatic life. Excess fertilizers can cause algae blooms, depleting oxygen in the water and suffocating fish. Pesticides can be toxic to fish and other organisms, disrupting the food chain. Sediment runoff can cloud waterways, reducing sunlight penetration and harming plant life.

Mitigated Soil Erosion

Effective drainage systems reduce soil erosion, preserving plant health and preventing adverse effects on landscapes and concrete areas. Soil erosion caused by excessive stormwater runoff can wash away valuable topsoil, reducing plant growth and crop yields.  It can also deposit sediment in waterways, clogging streams and rivers, and negatively impacting fish habitats. Furthermore, soil erosion can weaken the foundation of buildings and structures built on hillsides.

Enhanced Property Appearance

Clogged drains can lead to unsightly standing water. Maintaining them contributes to a visually appealing landscape, potentially increasing property value. A well-maintained drainage system promotes a clean and attractive outdoor environment, adding to the curb appeal of a property.

Preservation of Water Quality

Stormwater runoff often carries pollutants like oil, fertilizers, pesticides, and sediment. Well-functioning drains help prevent these pollutants from entering waterways untreated, protecting aquatic life and the overall health of our water ecosystems. Clean water is essential for human health, recreation, and healthy ecosystems. By preventing untreated stormwater from entering waterways, we ensure the quality of our water sources for generations to come.

Supporting Community Health

Reducing the risk of flooding and waterborne diseases benefits public health and safety. Properly managed stormwater reduces the likelihood of accidents, injuries, and property damage associated with flooding and water contamination.

How to Maintain a Stormwater Drain:

Regular Inspection

Regularly inspect storm drain grates, clearing debris like leaves and sticks to ensure optimal water flow. During winters, check for ice and snow buildup that might cause blockages. If you notice signs of rust, cracks, or misalignment in the grates, contact a professional for repairs to prevent further issues.

Professional Assistance

Due to potential safety risks associated with harmful pollutants and the complexity of some issues, leave the task of opening and unclogging stormwater drains to experts.  Professionals possess the necessary expertise, tools, and safety gear to handle these tasks effectively.

Landscape Maintenance

Consider incorporating features that improve stormwater absorption in your yard. Filling your landscape with pebbles, sand, and vegetation can be beneficial. Planting native plants with deep root systems, such as rain gardens filled with perennials, shrubs, and flowering plants, is a great option. These plants not only enhance curb appeal but also aid in stormwater absorption and filtering pollutants before they enter the drainage system.

Signs of a Clogged Stormwater Drain

A clogged stormwater drain can cause a variety of issues on your property. Here are several important indicators to be mindful of:

  • Standing Water: This is the most obvious indicator of a clog. After a moderate or even light rainfall, if you notice stagnant water accumulating around or even inside the storm drain, it suggests a blockage preventing proper water flow.

  • Slow Drainage:  Pay attention to the rate at which water drains away after rainfall events. If you notice a significant slowdown in drainage compared to usual, it could be a sign of a partial clog within the system. This can occur even after moderate or light rainfall.

  • Water Seepage into Foundation:  If you observe water entering your basement walls or foundation, it could be a sign of a blockage or overflow issue within the stormwater drainage system. A clogged drain may cause water to back up and seep into these areas, potentially leading to water damage and mould growth.

  • Foul Smell: An unpleasant odour emanating from the stormwater drain indicates a long-standing blockage that requires professional attention. The odour may be caused by decaying organic matter, stagnant water, or even sewage backup if the clog affects both systems.

Types of Stormwater Drainage Systems

Different types of stormwater drainage systems exist, each playing a specific role in collecting and conveying stormwater runoff. Here is an overview of several typical systems:

  • Curb and Gutter Systems: These are channels along roadsides that collect water and direct it to underground pipes through grates.

  • Catch Basins: These are underground structures with grates that trap debris and sediment before water enters the drainage system. Catch basins require regular cleaning to maintain functionality.

  • Swales: These are grassed, shallow channels that naturally filter and convey stormwater runoff. Swales are often used in landscaped areas to promote infiltration and reduce the burden on traditional drainage systems.

  • Underground Pipes: This network of pipes transports collected stormwater to a suitable outlet, such as a stream, river, or infiltration basin. The size and capacity of these pipes are crucial for effective stormwater management.

Regulations and Environmental Impact

Local regulations play a crucial role in stormwater management. These regulations may dictate factors like the design, construction, and maintenance of stormwater drainage systems on both private and public properties.  Well-maintained drainage systems contribute significantly to a healthier environment by:

  • Preventing Pollution: By effectively capturing and filtering stormwater runoff, well-maintained drains help prevent pollutants from entering waterways, safeguarding aquatic ecosystems and public health.

  • Promoting Water Conservation: Certain green infrastructure practices, like rain barrels and permeable pavements, can encourage water infiltration back into the ground. This helps conserve valuable water resources and reduces the strain on traditional water treatment facilities.

  • Mitigating Flooding: A properly functioning stormwater drainage system can significantly reduce the risk of flooding by efficiently channeling excess water away from populated areas.

Sustainable Practices and Green Infrastructure

Green infrastructure solutions can be incorporated into stormwater management plans to promote water conservation and filtration. Here are a few examples:

  • Rain Barrels: These collect rainwater from rooftops for later use in watering gardens. Rain barrels help reduce reliance on municipal water supplies and promote water conservation.

  • Permeable Pavements: These pavements allow water to infiltrate the ground instead of running off into traditional drainage systems. Permeable pavements can be used in driveways, walkways, and parking lots.

  • Green Roofs: Vegetated rooftops can help retain and insulate buildings. Green roofs not only provide aesthetic benefits but also help absorb and filter rainwater, reducing the burden on stormwater drainage systems.

The Future of Stormwater Drainage

Emerging technologies and trends in stormwater management offer promising advancements in efficiency and sustainability. Here are a couple of examples:

  • Bioretention: This technique utilizes plants and soil to filter and store stormwater runoff.  Bioretention facilities can be incorporated into landscaping designs and offer aesthetically pleasing solutions for stormwater management.

  • Green Streets: These streets incorporate green infrastructure elements like swales and rain gardens into their design. Green streets not only manage stormwater runoff but also provide aesthetic and ecological benefits for urban environments.

DIY vs Professional Maintenance

While it's advisable to regularly clear leaves, debris, and trash from grates to prevent blockages, for any major issues, seek professional help.  Here's a breakdown of appropriate actions:

DIY Tasks

  • Regularly clear leaves, debris, and trash from grates to prevent blockages.

  • Keep the area around the drain clear of vegetation to prevent root intrusion.

  • Occasionally hose down the drain (avoiding high water pressure) to remove minor buildup of dirt or sediment.

Professional Assistance

  • Unclogging drains with complex blockages or potential safety hazards.

  • Repairing damaged grates, pipes, or other components of the drainage system.

  • Installing new drainage systems or modifying existing ones.

While fixing clogged drains yourself can save money, for bigger problems, calling a professional plumber is the smarter choice. Professional plumbers have the knowledge and experience to diagnose the issue quickly and use specialized tools to get your drains flowing smoothly again. Consider a trusted company like CPE Industries - their expert plumbers can handle any drainage issue efficiently, so you can relax with peace of mind knowing your system is in good hands.


A well-maintained stormwater drainage system safeguards our properties, environment, and health. While professional help is needed for complex issues, individual efforts matter. Be a responsible homeowner by regularly clearing drains and incorporating water-infiltration features in your landscape.

Beyond your property, consider community involvement. Collaborate with neighbors, advocate for green infrastructure policies, and educate others about stormwater's importance.

The future holds promise. Collaboration across sectors, investment in research, and public engagement will lead to innovative solutions that transform stormwater from a burden to a resource. Collectively, we can work towards securing a more robust future for everyone.

Frequently Asked Questions

1. What's the difference between a stormwater drain and a sewer drain?

Stormwater drains collect rainwater runoff from roofs and streets. Sewer drains transport wastewater and sewage from homes and businesses to treatment plants.  Stormwater is released untreated, while wastewater undergoes treatment before release.

2. How can I tell if my house is connected to the stormwater drain?

3. What are some signs of a clogged stormwater drain?

4. Can I fix a clogged stormwater drain myself?

5. What are some benefits of hiring a professional plumber for stormwater drainage issues?


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