How to Choose the Right Trench Drain

Did you know that the average US family spends more than $1,000 in water bills each year? Some studies indicate better water conservation could lead to huge savings. A quality trench drain system could be a big contributor to making those savings.

But many people don't have a good understanding of this common drainage system. They aren't certain how it's used to improve drainage at their home or business. Without this basic understanding, it's impossible to make an informed choice on the best drainage system for you.

If you're looking for a comprehensive guide to trench drain systems, you're in the right place. We've put together a comprehensive guide, covering all the information you could ever need on this important drainage system.






What Are Trench Drains?


Trench drains, also known as channel drains, aren't too difficult to understand. Their simplicity is one of the things that makes them so popular and easy to use.

This kind of drain uses a long surface. allowing water to travel from one area to another. It's a simple way of dispersing surplus liquid, taking water from an area it could cause harm and channeling it into a safer area. Making use of a simple design with no moving parts, these drains have an enormous potential capacity and can stand up to plenty of punishment.

A simple way to visualize a trench drain is to think of your roof gutters. Then imagine them set firmly into the ground and covered with a grating, diverting falling water into a more suitable area.



Trench Drains are made of grates, channels, and outlets

So How Do They Work?


The simple power of gravity is all that's needed for a trench drain to function. Drains are always installed on a slight incline, or feature a built-in incline, allowing water to flow gently away from the area of concern.

The principle really is simple but effective. Water drains almost as it usually does, but the drainage system contains and directs the flow.

Eventually, it finds its way into a stop tank. From here, the water can safely be removed for disposal or use elsewhere.



A counter directional trench drain run with a center inline catch basin outfall. In this configuration, half the drain runs from east to west, half the drain runs from west to east. The outlet is the center inline catch basin.


Where Are Trench Drains Used?


Trench drainage systems are versatile, cheap, and effective, so it's no wonder they're used in a variety of residences, businesses, and public locations across the world.

One of the most common businesses where you'll find this kind of drain is airports. British airports are responsible for introducing trench drains to the world. The drains were developed specifically to keep airport runways clear, with a demand for high drainage capacity and low maintenance requirements foremost in the designers' brief.

They're used anywhere there's a need to drain away excess water, so the possibilities really are endless. You might see this kind of drainage system at a school, warehouse, shopping mall, or anywhere else with an outdoor area. They're also popular at locations that process high levels of industrial liquids, like breweries, and on construction sites, where it's necessary to keep the site from becoming inundated.




Trench drains with pedestrian traffic are usually heel proof and ADA


Domestic Trench Drains


Trench drains aren't just used in businesses. They're found in residential properties across the world too. If you take a look around your own home, you might find that you have some around your house and garden.

Trench drains often support more traditional roof guttering systems, allowing the water that drains from a roof to travel safely to a more suitable area.

They are often present in gardens, helping to prevent grass and flowerbeds from becoming inundated with water. Driveways are another common location, allowing water to drain from large expanses of concrete. A driveway trench drain is a great way to avoid costly maintenance bills around your property.



Concrete encasement for an 8" wide residential trench drain


Interior Trench Drains


You'll often see trench drains used indoors too. They're commonly used in bathrooms, and you might see them close to your shower, stopping large puddles from forming on the floor.

Swimming pools almost always use trench drains. You'll see them around the edge of the pool, helping to deal with any water splashing out of the pool. Residential garages are another popular trench drain location. They're perfect for channeling away excess water after you've washed your car.

Typically, indoor drains will cost much less than outdoor drains. They're smaller, lighter, and don't need to be as tough as their outdoor counterparts. They often use simpler materials and the trench drain installation process is likely to be much easier.



Leveling a pre sloped trench drain system during a brewery installation


Why Are Trench Drains More Effective Than Other Kinds of Drainage Systems?


One of the most important properties of trench drains is their ability to prevent erosion. When water pools without control, it can damage the ground, leading to hazardous conditions and even flooding in the long term.

They can also stand up to plenty of punishment and require minimal upkeep, so they're ideal for heavy use.



A heavy duty trench drain keeps an airport dry





Environmental concerns are becoming ever larger in the public consciousness. Drainage systems can play a big part in helping to protect the environment, or even improving a business's eco-credentials.

Efficient drainage systems can avoid environmental damage, like soil erosion and flooding. With better management of your own property, you help protect the land around you.

You can even use trench drains as a way of preserving water. Instead of leaving water to stand, drains may channel into a storage container, for various uses. Or it could be sent directly into a rain garden, helping thirsty plants to grow.



A trench drain installation with catch basin to capture debris before it enters the waterway


The Dangers of Pooling Water


When water has nowhere to go, it forms a pool on the surface of the ground. This can have a wide range of negative effects. As well as the obvious slip hazards, they can damage even the toughest of surfaces, causing cracks and erosion.

Pooling water is especially prevalent and dangerous in urban areas. This can include busy road networks, parking lots, and workplaces with large, paved areas.

The problem is that the water has nowhere to go. By transporting the water away from an inundated area and into a tank, you can keep an area safer, as well as save money on overall maintenance costs and keeping up with safety requirements.




Water pooling in an airport is a risk. Trench drain are a good way to keep runways dry.

Choosing the Right Size for Your Trench Drain


When it comes to drains, size matters. A draining professional will spend a lot of time thinking about the optimum drain size for a given area. Drains generally come in pre-selected widths, from 4" to 16". An expert can help you determine the exact size to suit your needs.

As a general rule, 5", 6", 8", and 12" drains are suitable for residences and driveways, or if you are looking for a drain for a commercial property, you 6", 10", 12", and 14" are common. For more heavy use, you should use a minimum width of 8"

It's important to think carefully about the ways different sized components can fit into a specific environment.


Safety First


Safety is important to any business or residence. And in the case of trench drains, you're dealing with concentrated amounts of liquid at floor level, which can potentially pose a hazard if left to get out of control.

As long as the drain is well-constructed and maintained properly, it will comply with all safety regulations. The main potential hazards are a broken grate or trip hazard. Top-quality materials and expert installation should prevent either of these issues from occurring.

You'll need to think carefully about specific safety concerns before the installation process begins. Sometimes particular quirks of a specific location can mean a different approach is necessary. Products like anti-slip covers are available.



Concrete being poured for a parking lot installation


Determining the Correct Flow Rates


The speed with which water flows through the drainage system is important. If the flow is too little, the drainage system might be ineffective. If it's too great, an excess of water may overwhelm your dump location. The best way to establish the right flow rate is with a calculation.

The maximum runoff rate for a surface equals the product of the maximum rainfall intensity, the area being drained, and the coefficient of runoff. This must be strictly less than the channel flow capacity of the pipe, which depends on the slope, size, and material of the pipe.

This may seem a little complicated, but it's a commonly used process that drainage professionals are familiar with. This is calculated using a special formula called Manning's equation.



Water flowing out the side outlet


Different Trench Drain Materials


Wherever trench drains are found, they're made of different materials. There are three particularly common materials used to construct drains, but there are many others in use.

The material chosen for an individual trench drain design can vary wildly. Factors in making the choice will include the positioning of the drain, the area of deployment, and the amount of water channeled.

Different mixes of materials are often used to create different parts of the drain. For example. you could end up with an HDPE drain in a high-performance concrete shell, covered by a stainless steel grate.



Trench drains can be made of HDPE, Polymer concrete or stainless steel




Trench drain made of HDPE



High-density polyethylene, commonly known as HDPE, is a cost-effective material with many common applications, such as in milk bottles and cutting boards. Drains made of this material are normally made in a factory before being transported in sections to the installation site.

HDPE has many properties which lend themselves to using it for drainage. It has high resistance to impacts, corrosion, and chemicals, which combine to make this a particularly durable material. Despite this, it has low weight and is highly malleable, which can potentially result in significant cost savings.

There are some flaws to using HDPE for drains though. With its high coefficient of thermal expansion, the length can change substantially in hot or cold conditions, which could result in it separating from its surrounding components. It also has a shorter lifespan than other materials, such as polymer concrete and stainless steel.



Trench drains made of polymer concrete

Polymer Concrete


Polymer concrete is ideal for areas experiencing sustained weight loads passing over them. For example, a warehouse loading area, which might have heavy-duty trucks passing over them day in, day out.

Like HDPE, it is highly resistant to corrosion and chemicals. In addition to this, it has high compressive strength, which means that it is well suited to bearing heavy loads. In contrast to HDPE, it is far more capable of standing up to extreme changes in temperature, generally able to work up to 82 degrees Celsius.

The main drawback with polymer concrete drains is that they tend to be much more expensive than other materials. As well as their higher production costs, the fact that they are heavier than a lot of alternatives means a substantial increase in the manpower needed to install them.




304 Stainless Steel is both sanitary and non corrosive

Stainless Steel


Stainless steel works best in areas with a high variation of extreme temperatures. It can stand up well, even in punishing heat and thaw cycles. This is normally galvanized steel, which is extra strong and coated with a zinc coating to prevent rust.

Stainless steel is more expensive than some other materials like HDPE, but its all-around durability means it's often the best option for high-pressure environments.

One use for stainless steel drains is in breweries, where high-temperature liquids and various chemicals will flow through the drain, and vehicles like forklifts continually pass overhead. It's also extremely easy to clean, thanks to its smooth, nonporous surface, so it's almost impossible for substances to become stuck in the drain.



Other Materials


Lots of other materials are used in the manufacture of trench drains. Some of these options are cheaper but somewhat less effective than the three preferred materials.


Cast Iron


Cast iron has many of the same properties as steel but ultimately has a shorter operational lifespan and is more prone to damage from the elements. It's sometimes used in gratings and other exterior parts.

Cast iron has a rust-proof coating. But long term exposure to the elements means the coating's effectiveness can break down over time, reducing the lifespan of the drain.

Although it lacks the long-term durability of steel, it's still a powerful material used in some high-load grade drains.


Cast Iron trench drain installation



While plastic is one of the cheapest materials to make a trench drain out of, it's not as durable as the others and is prone to wear and tear. In particular, if used in an area that experiences extreme cold, it can shatter if impacted. Generally, low-grade plastic is only present in low-traffic areas.

While some of the individual components of the drain may be made from plastic, a high-quality trench drain will generally be made of something a little more sturdy, especially if it's based outside or at a business location.


A trench drain channel made of polymer


How to Design the Right Trench Drain



Although trench drains are a relatively simple way of draining water, it's important to think carefully about each step of the design.

Professionals will carefully study blueprints and technical specifications to ensure the best possible setup. They'll consider lots of factors, including the type of site, the amount of water that needs draining, and the pressure the drain is likely to be under across its operational lifespan.



Sequential pre sloped channels are being set together to create a long run


Load Classes


Every drainage system has a different load class. This class indicates how much weight a drain can take. While moving up through the classes adds a little more expense to the installation and design, choosing too low of a class is costly and dangerous.

As a rule, the higher grade drains will need a little more maintenance and cleaning, since they'll be taking more punishment on a day-to-day basis.

They're also likely to cost a little more than the simplest drains. These tougher drains need higher quality material to stand up to the extra weight.




Able to stand up to a max weight of 3,337 lbs, this load class is only suitable for lightly trafficked areas, likely on a residential property. Use this class in a garden or pedestrianized area. It can handle small amounts of pedestrian and bike traffic.




Capable of managing 28,100 lbs of weight, B class drains would be well-suited to areas likely to see a moderate amount of vehicular traffic, such as a residential driveway.

If you live in a quiet suburban area, you'll probably find B-class drains on the sidewalks close to your home.




The C load class works well on quieter roads or small parking lots. With a capacity of 56,200 lbs, it can handle most vehicles commonly seen on the roads.

Municipal or commercial parking lots with quite high vehicular traffic often employ C load class drains.




For areas with heavier traffic, a higher weight class is necessary. D class drains can handle up to 89,920 lbs.

You might see D class drains in use on busy freeways, or in industrial areas expecting heavy vehicle traffic, like warehouse loading areas.




E is the class for when you need things as tough as possible. This is the toughness found at sites that are extremely busy with large vehicles passing regularly.

Capable of withstanding up to 134,800 lbs of weight, a drain with this level of toughness can handle even the enormous maintenance vehicles which will lumber back and forth across its surface, day in, day out.

Expect to see E-class drains in heavy use industrial areas, like ports and docks.




A drainage system isn't something you'll want to replace every year or two. The installation process can cause a lot of disruption, so it's important to ensure the lifespan of your drains is as long as possible. That said, these systems are naturally long-lasting, commonly serving homes and businesses for many decades.

The more money you invest in your drainage system, the longer it will last. Stronger materials and a more considered set-up will allow it to meet challenges more readily.

It's also important to ensure that professionals install your drainage system. Poor-quality installation can contribute to the system breaking down or becoming damaged.



Proper installation is as important as proper product choice


Different Types of Trench Drain


There are so many different kinds of trench drain with subtly different features. Each one has its own advantages and s particularly effective in specific areas.

Each kind has lots of options for customization, so you can make adjustments to ensure the drain suits your needs.

Model 600


This super-reliable pre-sloped drain is one of the most popular residential trench drains on the market. The Model 600 fits in well to both residential and industrial applications.

Constructed from HDPE and featuring 0.7% – 1% pre-sloped channels with locking and bolted grates, it's hugely versatile, able to stand up to the pressures of heat and chemical contact.

It's versatile too. The Model 600 comes in separate units and can be constructed onsite to your particular specifications. That means you can choose the right number of units to suit your needs, then customize them with a huge choice of different grates and other accessories.



Swiftdrain 600 with galvinized steel grates


Model 200


The Model 200 is another popular trench drain design, slotting effectively in homes and businesses.

Constructed from fiber reinforced concrete, it's extra tough and is load class E, meaning it can take up to 60 tons of weight!

It's this sheer toughness that means the Model 200 is reliable in even the most challenging environments. It's used on busy roadways and areas of heavy industry, including airports and warehouses.


Swiftdrain 200 fiber reinforced concrete trench drain




The Brewmaster is a trench drain designed specifically for breweries. This is the best channel drain for this specific environment.

Made from stainless steel and designed for low upkeep and quick installation, it's perfect for the busy brewery world, where heavy vehicles, high temperatures, and a variety of chemicals are facts of everyday life.

The Brewmaster is an excellent example of the versatility of a commercial trench drain. They offer so many uses and customization options to work perfectly in challenging and specialized areas.



Swiftdrain 600 Brewmaster trench drain with 304 stainless steel grates


Trench Depth Styles


There are two key ways a trench drain can be inclined. Both of these have their own advantages.


Regular Depth


Smaller drains tend to have a regular depth for their entire length. This helps to maintain smooth, consistent drainage and is often used on smaller drains, or where the natural incline aids water distribution.

Regular depth drains are also simpler and easier to install, requiring less material and preparation.



Pre slope and neutral slope configurations

Built-In Falls


Some drains are constructed with built-in falls, allowing large concentrations of water to flow more easily downwards. They help the system harness the power of gravity.

These extra falls can cost a little more, but add a huge amount of extra capacity to the drainage system. Extra work is necessary before installation to carve out the space for these falls.


Pre-Cast and Cast-in-Place Drains


There are two different ways in which trench drains are installed, pre-cast and cast in place. Each style has pros and cons and may suit different requirements.




Pre-cast drains are pre-made in a factory, using molds with pre-determined units of height and width.

The offsite casting process can add to the cost and logistical difficulties of drain installation. The drains will also require joints in order for the smaller pieces to fit safely together.



A pre cast trench drain being installed



If your drains are manufactured onsite, that's called Cast in Place. Engineers will use portable mold and tethering devices to form the drain's shell onsite, before installing the different components there and then.

Cast-in-place drains are cheaper to install and don't require a large transport operation, or joints. But they come with several downsides. Inclement weather conditions can make installation impossible rainfall can cause delays to works.

It's also harder to add made-to-order components, which may need a factory environment to be properly produced.



Cast in place trench drain installation with a frame and grate pour in place concrete encasement


Trench Drain Components


A key advantage of trench drains is their lack of movable parts. The drains were designed for simplicity of maintenance and construction. But there are still several important parts that play a role in the drainage system.

Having a basic understanding of the different parts allows you to make better decisions when it comes to commissioning, designing, and maintaining the drains.



Trench drain parts and components




This is the most important part of the drain. The channel, or trench, is the component that allows water to travel from one area to the other.

Generally, the channel comes in different segments which are put together on-site to form a longer trench. Each section comes with an optional outlet section, allowing flexibility for water to drain off at different points.

Channels are either pre-sloped or neutral and inclinations are available in a variety of different levels.


HDPE trench drain channel with anchors for #4 rebar




Heavy-duty construction covers are sometimes used to protect the trench during building work in the area. These tough covers prevent concrete and other debris from clogging the trench.

These covers slot over a grating and are normally made from a stronger material. They need to be able to stand up to plenty of punishment while heavy construction is going on around them!

One use for these covers is during periods of unusually heavy activity when the drain needs a little extra protection.




Drains made from lighter materials like plastic or HDPE may need a little extra protection to keep them from breaking down or becoming damaged. Generally, the frame is made of a tougher material, like concrete, providing maximum protection.



Trench drain frames make this rated class D for forklifts and heavy duty traffic




The grating is the standard barrier that prevents a trench drain from getting clogged up with leaves and other outdoor debris.

Since trench drains are positioned on the floor, they're vulnerable to falling leaves. They're also likely to take a lot of punishment from people stepping on them and in certain circumstances, vehicles driving over them.

The trench drain grate also presents people and vehicles passing overhead from falling into the drain, so it's an important safety concern.



Galvinized steel grates with horizontal slots


Decorative Parts


Many trench drains feature decorative elements. After all, drainage systems aren't naturally the most eye-catching features, so it's nice to spruce them up a little!

These normally come in the form of a specially designed grate. A variety of different styles are often used and they can be specially designed to blend in with their surroundings.

These decorative parts are built to order to suit any area, forming an unobtrusive pattern on the ground that passers-by may not even notice.



Decorative trench drain grates


End Cap


The end cap caps pipes both above and below ground. It provides a solid end to the drain system. Opening or closing the end cap will adjust the flow intake when necessary.



Fiber reinforced concrete trench drain with galvinized steel end cap


Side Outlet / End Outlet


The outlet is the portion that lets out into underground sewerage. The outlet is normally made of a light, but durable material, like HDPE. Trench drains can also be configured with bottom outlets.


Trench Drain with 4" side outlet


Catch Basin


The catch basin is the area where the water drains into. The size of the basin will vary significantly depending on the application of the drainage system and the expected water intake.

It's important to choose the right capacity for the catch basin. If it fills up while water is still trying to drain in, the whole system will break down. An oversized basin can take up too much space and lower the efficiency of the drain.

The basin also needs to be constructed from a robust material, since it will need to stand up to lots of drainage coming in, along with the usual freeze and thaw cycles. Since it acts as a filter, preventing debris from entering the wider drainage system, the catch basin may need cleaning more regularly than other parts of the drain to ensure it functions properly.



Inline catch basin made of hdpe with 2 side outlets


Anti-Theft Devices


Anti-theft locking devices are an optional extra, used on many trench drains. You might think a drainage system wouldn't be vulnerable to thieves. In fact, it's not uncommon to see drains targeted by thieves or vandals, especially when they're constructed from metal, which has value on the scrap market.

Adding a locking system to the frame will keep it firmly rooted in the ground.


Drain Installation


The process of installing a trench drain isn't overly complicated, although for best results it will require a fair bit of forethought and maybe some hard physical labor.

The first step is planning. The optimal placement of a drain should allow it to collect surplus water and transport it to a more suitable area. The trench for the drain must also be carefully measured, ensuring it's the perfect width for the drain to be installed.

The installation process itself is hard work, depending on the surroundings. That's why anyone looking to install a quality drainage system on their property will need drainage experts to help them design and install the system. While digging through a dirt lot might not seem too hard, installing a trench drain in a concrete driveway is naturally going to take a little extra effort.



Trench drain T installation




The planning process is extremely detailed and complicated. Everything from the topography of the area, to the soil type and local vegetation will need to be considered to design an optimal drainage system.

Drainage professionals will carefully assess the area before moving on to deciding on the best materials for the different drain components.


Drain Installation


Once the planning stage is complete, the drain can then be installed. Drainage professionals will dig out a trench for the casting and drain.

This is the most important part of the process and it is crucial to follow the precise measurements laid down in the design process.


Perimeter drain corner installation


Outlet Design


One of the most important elements of the drainage system is the outlet. After all, the function of the trench drain is to move water from one location to another, so there has to be a safe place for water to be discharged at the endpoint.

You can channel water into a special area of your property, like a pond, sloped lawn area, or storage tank. In some cases, the outlet could run into larger, underground wastewater systems. For low-intensity drainage systems, a pit called a soak-away is often used, storing water on your property before slowly draining it into the surrounding soil over time.

Designing and connecting the drains to a safe and efficient outlet is one of the most important parts of the process. Giving extra consideration to wastewater recycling can help you lower your utility bills and add efficiency to your home or business.



A t connection side outlet installed on a fiber reinforced concrete channel




At the end of the installation process, the drain should be carefully inspected to ensure the process has run smoothly. This inspection should be conducted at least 24 hours after installation, to ensure the structure has settled.

The covers should be removed and the drain itself inspected for any signs of damage, poor installation, or clogs. The grating should then be placed back over the drain and the entire structure carefully secured.

There are a lot of different things an expert eye will pick up on during this first inspection. If everything isn't just so, a reputable company will fix the issue before moving on.



Inspecting level of a trench grate making sure its flush with the surface

Trench Drain Maintenance


Despite their lack of complicated parts, trench drains still need some degree of maintenance for optimum functioning.

This normally comes in the form of an annual clean. Even with the best grating in the world, a trench drain in constant use is inevitably going to experience a little clogging after a time. Raindrops have small particles of dirt in them, while tiny pieces of debris and insects will naturally break through a grating in time.

It's important to remove the grate safely when cleaning. It's also a good idea to think carefully about the cleaning products you're using, as some substances will react badly with drain materials and could cause damage to the system (some drains will come with a guide). The catch basin may need cleaning more regularly.



Trench drain installation for a driveway


Things to Avoid


There are several things that can go wrong with trench drains, but as long as you know what to watch out for, you'll be able to avoid problems. Simple diligence will resolve most issues.



Forming a trench drain for a driveway


Poor Installation


When a trench drain system is poorly-installed, this can cause plenty of issues down the line. Using the wrong materials or not taking enough care with installation can lead to the entire system suffering from weaknesses or breaking down under pressure.

One of the most common mistakes made by inexperienced companies is failing to secure the drains during the installation process.

Experts will use items known as "chairs" to securely anchor the drain in place during construction. If the installers don't use chairs, the structure can come loose and may be incorrectly aligned on installation. This makes the entire structure far less sturdy and can apply extra pressure to joints.


Expansion joints are always a good idea


Drainage Experts


As you might have gathered from reading this article, there's a little more to drainage than there might have seemed at first glance. The layman may be able to buy a basic drain and install it, but they're unlikely to understand the many intricacies that go into creating a successful system.

That's why there are professionals dedicated to the design, installation, and upkeep of drainage systems. The best professionals have studied all the different kinds of drains and know which specifications are likely to produce the best results.

What's more, they have the experience of installing a huge variety of different drains in all kinds of locations and circumstances.


Trench drains mitered to size on site


Don't Let Your Money Drain Away


Trench drains can help you keep your home or business well-drained. They'll allow you to avoid problems with erosion, keep your surroundings safe, and avoid unnecessary delays in your business.

By engaging an expert and experienced drainage company, you'll be saving money in the long term. It's a valuable investment that can increase the value of your property or business.

If you're having trench drains installed at your business, it's important to work with professionals to ensure a good job. Contact Swiftdrain today and find out how their years of experience in drain installation and maintenance can help you. When it comes to drainage, no job is too large or small, and they can work with you to come up with a unique solution to your drainage problems.