What is a rain leader? A rain water leader is a pipe that collects the water discharged from your gutters and downspouts, and moves this stormwater away from your home.


Stormwater management for homes centers around protecting your home from the disastrous effect that out of control storm water creates.  Rain leaders are an important part of every stormwater management plan because they specifically eliminate the toll that stormwater takes on the foundation of your home.  The stormwater collected by your gutters and discharged out of your downspouts has the potential to erode and begin to destroy your home’s foundation if left unmanaged. Rain leaders completely prevent this.  They keep your basement dry, prevent your flower beds and expensive landscaping from washing out, and keep your lawn from developing large pools of water. Rain leaders can even be set up to funnel water into a rain garden on your property or to supplement a landscaping irrigation system.  As you can see, rain leaders are a crucial part of any home’s stormwater management system.


So how can you tell if your home has rain leaders?  Check the end of your downspout. If it connects to a pipe that heads underground, you have rain leaders.  If your downspout dumps out directly on to the ground, you may have a disconnected or forgotten rain leader system, or your home simply does not have them.  If you notice a pipe going underground near your downspouts there is a good chance that your home has an abandoned rain leader system. We can often work with and reuse a large part of this existing piping to minimize excavation for a new fully functioning rain leader system.


Maintaining the rain leader system on your property is straightforward.  In fact, well installed rain leaders don’t need much attention. At most, we recommend an annual inspection and drain cleaning to ensure they don’t become clogged.  This is because rain leaders pass rain water, and in turn, whatever the rain water is carrying.  Leaves, twigs, moss, and sediment from your gutters flow through your stormwater pipes and can create clogs and blockages.

Because of their shallow depth, rain leaders can also experience clogging root intrusion. If the clog persists, a heavy rainfall could create a backup in your rain leader system, defeating the rain leaders purpose and potentially channeling water into your basement.  Drain cleaning is a great way to ensure your rain leaders always work at maximum efficiency.

As a homeowner it is also a good idea to occasionally visually inspect your rain leaders and the condition of your property during or shortly after heavy rainfall.  It is important to be aware of any potential problems or slow draining rain leaders before they become a real problem.

rain leader cleanout installation with mulch

Above is an example of a cleanout being added to an existing rain leader system. This allows the pipe to be accessed and easily maintained. After installing the cleanout, we pained it black and mulched the area so that it would blend in seamlessly with the landscaping.


Despite their usefulness, not all homes have rain leaders.  Rain leaders aren’t a necessity if your home does not have flooding or water problems when it rains.  However, if these types of problems currently affect your home, you may want to consider having rain leaders installed.

Symptoms of stormwater issues that rain leaders help include:

  • A damp or frequently flooding basement
  • Pooling water close to your foundation or in your yard
  • Overwhelmed basement stairwell drains
  • Mulch or sediment washing away during rainfall

Most rain leader systems can be installed at a very reasonable depth with minimal excavation and ground disturbance.  If you are considering stormwater management for your home, rain leaders can be put in with ease.

Storm drains are designed to carry clear water waste from rain water and some specialty fixtures. Typically, large flat roofs will require a storm drainage system to remove trapped water, as the weight of the water could quickly damage the structure of the roof in a heavy rainfall; to prevent this, rain water roof drains are installed to drain the water to a leader, then to a storm building drain, and then finally to the public storm water disposal system.

In residential construction, storm water is less of a concern, but still requires some provisions to prevent basements from flooding. When the foundation walls are completed, a perforated pipe called Weeping Tile, is placed around the footing; this will trap and drain away any ground water before it can penetrate the foundation. The following pic illustrates how Weeping Tile is placed around the Foundation Footing. In this pic, the Weeping Tile is wrapped with cloth, to prevent silt from entering the pipe (Weeping Tile).


Gutters and downspouts may also be connected to the weeping tile or drained away from the foundation. Weeping tile, where available, is connected to a public storm system, but in rural area’s, the water must be drained to a low area; such as a ditch, French drain or pumped away with a sump system.

Note: It is Not Recommended to drain your rain water from Downspouts into the Weeping Tile. Over time, debris will build inside the Weeping Tile, and prevent water from flowing.

Components Of A Storm Water Drainage System

Roof Drains

Roof drains come in dozens of different types and configurations to suit any conceivable situation, but there are two basic types; normal, which are completely open, and flow controlled, which limit the amount of water drained. The area of a flat roof and the maximum 15 minute rainfall for the area will determine the size and spacing of roof drains.

Rain Water Leaders

A rain water leader is the vertical drain(including any horizontal offsets) that carries rain water and clear water waste to the storm building drain. Rain water leaders are sized by the amount of water(in Liters) they are expected to be capable of draining. Leaders must be designed so that the expansion and contraction from intermittent temperature changes will not damage the piping system. As with sanitary drains, all rain water leaders must also be provided with a clean-out, located close to the base of the leader(within 3M).

In the following diagram illustrates the Rain Water Leaders for multiple roof tops, connecting to a Storm Building Drain, which terminates outside the building to the Storm Sewer.

Storm Building Drain

A storm building drain will convey storm water from a leader or sump to a storm sewer, combined building drain/sewer, or a suitable location(ditch). Storm building drains are sized according to the maximum rainfall in Litres, and graded according to the size and load of the pipe. The storm building drain extends one meter outside the building where it then becomes a Storm Sewer.

Storm Sewer

A Storm Sewer is the extension of a storm building drain, beginning one meter outside the building. A storm sewer will discharge the water to a public storm system or another appropriate place where the water can safely drain away. Because storm drains are not permitted to contain sewage, they are permitted to be drained to any area capable of handling the discharge.

Combined Building Sewer

The term combined, whether referring to the building drain or the building sewer, simply means that the storm and sanitary drains are connected together. A combined building drain is connected together, inside the building and a combined building sewer makes the connection more than one meter from the exterior of a building.

Connecting Plumbing Fixtures To A Storm Drain

In commercial / industrial buildings, there may be numerous fixtures that discharge clear water waste and is not required to be treated. These fixtures may be indirectly connected to a storm drainage system(check your local code). Fixtures connected to a storm system must have their discharge rates calculated so the drains can be sized (usually given in Liters per second or Gpm). Some fixtures that typically discharge clear water waste are:

  • Kitchen equipment
  • Air conditioners
  • Refrigeration equipment
  • Drinking fountains