The locate request comes first, and it is the law
Before anything goes into the ground, a locate request goes to Ontario One Call. The organisation states plainly that requesting a locate before you dig is free, easy and it is the law, and that homeowners must submit the request at least five business days before digging (Ontario One Call).
What comes back is not a single rule but a set of instructions from each buried infrastructure owner, and those instructions differ from one another. One typical example given by Ontario One Call is to dig by hand within one metre of the markings. There is no universal hand-dig distance, so the instruction you receive is the one that governs. A locate is valid for at least 60 days from the day you receive it, and possibly longer depending on the owner.
The scope is wider than people assume. A fence post, a tree pit, a rototiller working 150 mm into the soil and an excavation for a patio base are all digging. The cost of not calling is not a fine in the usual case, it is a cut gas service or a severed fibre line and a bill for the repair.
Grading, drainage and the front yard
The City of Ottawa's own landscaping guide is unusually direct on this point. It states that you are not allowed to change the grading of a property, because property grades are designed to direct water away from the home to prevent damage to foundations, flooding to properties and soil erosion. It adds that water cannot be directed to neighbouring properties unless that is part of the approved plan, and it tells homeowners not to alter ditches, which serve a stormwater function (City of Ottawa).
For a Kanata homeowner this rules out the two most common shortcuts: filling in the rear swale to make mowing easier, and building the rear yard up so it is level with the patio. Both move water onto a neighbour's lot. If your yard holds water, the permitted approach is restoring the grade the lot was approved with, extending downspouts, and improving the soil so it can absorb what falls on it.
The same guide sets a front yard rule that catches people planning a wider parking area: 50 per cent or more of your front lawn must be dedicated to soft landscaping. Driveway widths are also limited by zone, with a 6 m maximum in the downtown and urban zones and a limit of 50 per cent of the lot width in the suburban and rural zones, and the combined width of driveway and walkway entering the City right of way cannot exceed 50 per cent of the total frontage.
Trees: the 30 cm threshold and the critical root zone
Ottawa's Tree Protection By-law 2020-340 regulates trees on private land as well as City land. On an urban lot of one hectare or less, a tree with a trunk diameter of 30 centimetres or more measured at 1.3 metres above grade is a distinctive tree, and a permit is required before it is removed, injured or destroyed. On urban lots larger than one hectare the threshold drops to 10 centimetres. Permit fees reported as of 1 February 2026 are $200 per tree for non-infill removals and $1,240 per tree where infill development is involved, capped after five trees, and permits must be posted on the property.
Those figures are taken from a summary published by an Ottawa arborist firm (Advanced Tree Solutions), because the City's own tree by-law pages return an error to automated reading and could not be verified directly for this guide. Treat them as a reason to telephone Forestry Services rather than as the final word. The point that matters is the principle: a large tree on your own lot is not automatically yours to cut, and injuring one, which can include heavy pruning or root damage, is covered as well as felling it.
The second tree rule is spatial. The City's landscaping guide defines the critical root zone as a radius of 10 cm from the trunk for every 1 cm of trunk diameter at breast height, so a tree with a 30 cm trunk has a critical root zone radius of 3 m, and a mature 60 cm maple has 6 m. You cannot dig within that zone without approval from Forestry Services (City of Ottawa). In Beaverbrook, where mature trees are the rule rather than the exception, that radius frequently covers the whole area somebody wants to excavate for a patio.
Driveways, walls and the Building Code
Any work on the hard surface entrance to your property where it crosses the City road allowance falls under the Private Approach By-law 2003-447, and a permit is required to construct, relocate, alter or close a private approach (City of Ottawa). Resurfacing an existing driveway without changing its size or slope generally does not need a permit, but widening one does, and so does cutting a new entrance.
Retaining walls pull in the Building Code once they reach a certain height in certain positions. Ottawa's guide states that a building permit is needed for retaining walls more than 1 m high when they are next to public property, next to access to a building, or on private property that is open to the public. Hardscape structures such as stairs and landings have to meet Building Code requirements for rise and run, guards, handrails, landing size and walking surfaces (City of Ottawa). A wall in the middle of a private rear yard may sit outside that trigger, which is exactly why you should ask building services about your own situation rather than relying on a contractor's recollection.
None of this requires the contractor to hold a licence, because no such licence exists for landscapers in Ontario. It does mean the contractor should know which of these rules applies to your job and should be willing to say so in writing before starting.
A short checklist before work starts
Locate request submitted at least five business days ahead, and the instructions from each utility read rather than skimmed. Grade unchanged, or restored to the approved plan, with nothing directed at a neighbour. Front yard still at least half soft landscaping. Any tree of 30 cm or more at breast height checked with Forestry Services before pruning or removal, and no digging inside its critical root zone without approval. Private approach permit in hand if the driveway entrance is changing. Building permit and engineered design where a wall over 1 m sits in one of the regulated positions.
Then the contractor checks: proof of commercial general liability insurance, a WSIB clearance number, which is valid for up to 90 days (WSIB), and a pesticide exterminator licence if anything is being applied. Get all of it before the first day on site, because none of it is easy to obtain afterwards.