header photo

Discovery Inspections



Here on beautiful Vancouver Island, we get a lot of rain, so it is often imperative for our homes to have dedicated drainage installed around the perimeter of the building and sometimes in the yard or inside the basement such as a sump pump system.

The perimeter drain plays a major role in protecting your property from water damage and keeps you from having a wet crawlspace or basement.

Here we will explain what perimeter drain systems are, how they work, other types of drainage systems and what homeowners should know about them.




What is a perimeter drain and how does it work?

Also known as a weeping tile, a perimeter drain is designed to keep ground water and surface water away from the foundation of your home. Most homes in BC will benefit from these drainage systems and in fact, they are required by code in new homes built today. Without them, water could quickly seep into your basement walls or floor, causing major damage to your property.

A perimeter drainage system is laid along the foundation and outer walls of buildings and leads away excess water. The water led away could be excess surface water from precipitation or it could stem from an elevated groundwater level (water table), which creates water pressure against the house.

When a house is constructed, a certain amount of dirt around the perimeter of the home is excavated. Once construction is finished, this dirt is put back into place, making it looser than the untouched soil next to it. Therefore, water runs more easily through this soil, which just happens to be right next to your basement or crawlspace walls. 

The drain system itself consists of perforated pipe that is installed underground circling the perimeter of your home. The tiny holes allow water to enter the pipe where it then can be drained away from the home’s foundation. The pipes are out of sight on most properties and are installed in a trench and then covered in layers of gravel and filter cloth to keep silt and sand out of the pipe. The trench is then backfilled with soil to help water flow toward your storm drain or a drywell/leech pit.

Some older homes were constructed with the perimeter drainage and weeping tile connected directly to the sewer system, which is not designed to handle large volumes of runoff. If your home’s weeping tile or perimeter drainage system is connected to the sewer, you may be at risk of contributing to an overload of the system, which can cause water backups. You may want to consider disconnecting your home’s drainage from the sewer system.


How can I tell if there is a problem with my perimeter drain system?

If you are noticing an active leak in your crawlspace or basement, then this is a sign that the perimeter drain might be blocked up or broken. Other signs could be staining on the foundation walls, visible efflorescence (discolouration) on the concrete, pooling water or squishy saturated ground outside the home, that does not dry out. These are all signs of a malfunctioning perimeter drain system, or it could be that the system you have is not sufficient to handle the amount of water that the property is now experiencing. Older systems might not have been designed to handle the changes in weather that we have all been noticing.


What can I do if there’s a problem?

The first step is for you to gather information by having the perimeter system inspected. When a reputable company like Drain Doctors on Vancouver Island inspects perimeter systems, they go into the basement or crawlspace and all around the perimeter to ensure that we see the whole picture so that they can provide the most detailed and accurate information and recommendations by a full investigation. They then will even use a CCTV scope camera to map out the entire system while looking for any blockages, breaks, root intrusion, or dips in the pipe.

If there are blockages in the pipe you can often clean the piping out by having a Hydro Flush/Power Auger of the system done to clear out any blockages. If it is the rainy season they would typically only auger and not add more water to the area with a flush at the same time. Generally, PVC Perimeter drain systems are very low maintenance if designed well, but like everything in your home there is a little bit of upkeep needed to keep everything flowing and working well!

A good tip is to always ensure that your gutter systems are not pouring water onto the ground right beside your foundation. Ideally, the downspouts need to be extended at least 6 feet away from the foundation.


What if the perimeter system is working fine but there is still water in my crawlspace or basement?


Perimeter drain systems are not the end-all-be-all for water around your home. There are other factors that can cause water to intrude your space and additional drainage solutions may be necessary to combat this. The water could be coming in from hydrostatic pressure or underground water veins (rivers) if your home is constructed below the water table.

One of the best solutions for this would be encapsulating the crawlspace, repairing and foundation cracks, and sometimes installing a sump pump system to drain excess water and relieve some stress on your foundation.

Other drainage options are installing trench drains along your driveway or in your garage, which look sharp in a concrete pathway trench drains may also be called channel drains and are an above-ground drainage solution.

Its materials are fixed in the ground within a long, narrow trench. Residential trench drains redirect water to keep it away from areas where it could cause damage, danger, or erosion. After it’s laid, the trench drain is connected to a local storm sewer or waterway to keep the ecosystem intact.



Go Back