Grading, drainage and swales

Drainage is the least visible landscape work and the only kind that prevents a five-figure problem elsewhere in the house. It is also the part with the most rules attached, because water leaving your lot lands on somebody else's.

Understand existing drainage before changing levels. Map the swales, downspouts and drainage outlets, and check the approved grading information where available. Discuss the proposed changes and any review requirements with the City before work; protect neighbouring properties and existing drainage routes.

Step two: measure before you diagnose. A level or a laser on the ground is worth more than an opinion. What matters: the fall away from the foundation over the first two metres, the high and low points of the lot, where the swale between you and your neighbour actually sits, and where every downspout discharges. Photographs during a real rainstorm are the most useful diagnostic available and cost nothing.

Start by documenting how runoff reaches and leaves the house, beds and swales. Ask a qualified contractor to assess the cause before changing levels or moving an outlet. A surface-water observation does not establish the cause of a damp basement.

Step four: re-grading and swales, done properly. Where a real correction is needed, the approach is to re-establish the design drainage pattern rather than invent a new one: fall away from the building, a swale carrying water along the property line as the original plan intended, and no discharge concentrated at a neighbour's foundation. On clay this needs care, because a swale cut into clay holds water rather than conducting it unless it has fall the whole way.

Before excavation. Request utility locates and follow the current instructions from Ontario Dig Authority, including any private-locate arrangements needed for your property. Confirm the locate package with the person performing the excavation before work starts.

Discuss the schedule early. Ask about design revisions, approvals, material availability, access and weather-dependent work. Agree the sequence and any dependencies with the contractor before fixing dates.

What to include when comparing prices. Ask for the proposed levels, outlet, soil quantities, access, disposal and surface restoration in the written scope. Confirm any review, surveying and permit costs separately. The site conditions and approved drainage solution should be understood before a price is fixed.

Discuss structural and ground conditions. Ask a qualified professional to assess the proposed dimensions, drainage, frost exposure and ground conditions. Confirm whether engineered drawings, guards or municipal approvals are needed; general web dimensions are not a design for your property.

Ask about qualifications and responsibilities. Request relevant experience, insurance information and the written scope. Ask which professional design input or approvals your project needs; verify any claimed professional title through the relevant official directory, such as the PEO directory. This site does not verify a contractor’s credentials.