Last summer was particularly dry for our region. However, towards the middle of the summer I started noticing dark stains and discolouration along the baseboards of our basement walls. The stains and getting more noticeable this summer. Can you suggest any possible causes?

There are several possibilities such as poor site grading and a lack of a gutter system. However, because your problem occurred during the driest time of year the most likely cause is over-watering the flowerbeds directly adjacent to the walls of your home. This problem will be exacerbated if the ground adjacent to these walls is sloped towards the building, pushing surface water from your yard down the exterior concrete foundation walls. This surface water and the over-watered flowerbeds can seep through the construction joint created when the concrete wall was cast on a previously poured footing. The stained baseboards are just a sign that there is more water in this area than your draintile can handle. Watering your flowerbeds moderately will probably help resolve the problem. Also consider planting shrubs and flowers that require very little moisture around the perimeter of your house.