Flood Prevention

Parking lot and drainage maintenance Tips

By: Mat Roersma, Featured in BCAOMA, Investor Magazine

As Vancouverites and property owners and managers we all experience BC’s south coast weather. With it comes large amounts of rainfall and occasionally the dreaded white stuff, snow. Maintaining properties with perimeter drain systems and parking lot catch basins during these times is vital to protecting the integrity of the property in and around your building.

We at Advantage have recognized that typically twice a year (usually spring and fall) we become inundated with phone calls regarding flooded parkades, basements etc due overflowing drains caused by the inadequate servicing of catch basins, pump stations, and associated drainage. Many times the source of the flood or back-up is simply one or more catch basins which have too much debris inside to allow water to pass through to the cities storm sewer. This causes them to back-up creating large pools of water on the surface that will find their way to the lowest point nearby, frequently inside the building.

The secret to saving money and mitigating risk is preventative maintenance, 99% of all parking lot floods are due to underservicing. Emergency services can become costly due to the large amounts of surface water that need to be hauled away, as well as an increase in time to remove the blockage and restore service. When catch basin servicing is carried out ahead of time the amount of time needed to clean them will be minimized, and the volume for disposal will be reduced significantly.

Keeping up on proper drainage maintenance is relatively easy to do, property managers can take a few minutes to walk around their parking lots and make a note of which catch basins may not be draining at the same rate as others. Also look for high levels of solids inside the catch basins (dirt, sand and debris) if any is visible above the water line have a reputable company service the catch basins. Remember that there will usally be a water line level in the catchment making it difficult to see the contaminants (see drawing below). If in doubt have an Advantage company representative come by free of charge to check for solids and other areas that may be of concern. Solids allowed to pass into the outlet tee when rain volumes become high, get carried into the pipes and create blockages that need to be cleared at significant cost.

We recommend not exceeding 50% of the catchment volume (the distance from the bottom of the catch basins to the bottom of the discharge tee to city sewer).


Here are some suggestions to save you money on catch basin servicing:

1) Areas that collect the most debris are usually under trees, vehicle wash areas and entrance points to the parking area. Watch these areas more closely and service them ahead of the rest, if your budget prohibits a complete service

2) Keep your parking area clear of leaves, dirt and debris. Picking up fallen leaves will reduce premature build up in catch basins

3) Watch for vehicles that leak excessive amounts of oil! Contamination of otherwise oil free catch basin solids is needless and environmentally irresponsible. The cost of disposing “oily” material is higher and will have to be hauled separately.

4) In commercial settings we occasionaly see restaurant tenants emptying grease trap waste into the catch basins. This material will congeal and solidify blocking the pipes creating the need to line jet the blockage clear. Be sure no type of foreign material is dumped down the drain.

Advantage Waste Specialties inc. offers numerous options to property owners and managers that not only include catch basin servicing but also line jetting, grease trap and septic hauling, oil tank removal and soil remediation.

Call AWS today for a free consultation on how to keep your building operating safe and on budget.