Permeable interlock looks much like ordinary interlock. The difference is underneath and in between: wider joints filled with clean angular stone rather than sand, sitting on an open-graded stone base that stores water and lets it soak into the ground. Rain goes down through the driveway instead of running across it.
It is a permitted access surface in Ottawa — section 601(5) of the Zoning By-law lists permeable pavement explicitly alongside asphalt and cement — so you can use it for the part of the driveway in the right of way as well as on your own property.
Why it suits Ottawa specifically
- Freeze–thaw. The open-graded base drains rather than holding water, and water that isn't trapped can't lift the surface when it freezes. Done properly, a permeable build is more frost-tolerant than a conventional one, not less.
- Spring melt. Ottawa's problem month is not July, it is the March thaw arriving on ground that is still frozen at depth. Storage in the base buys you capacity exactly when the lot has none.
- Lot drainage. If widening your driveway would push more water toward your foundation or your neighbour's, permeable solves the problem at source rather than moving it.
- No standing ice sheet. Surface water that drains away doesn't refreeze into the glaze that forms on a flat conventional driveway.
The rebate
| Practice | Maximum rebate |
|---|---|
| Permeable pavements | Up to $5,000 |
| Rain garden installation | Up to $2,500 |
| Soakaway pit installation | Up to $2,500 |
| Downspout redirection | Up to $1,000 |
| Certified landscape design | $500 |
To qualify you must be located in a Priority Stormwater Retrofit Area, and satisfy one of these four routes:
- Have completed a Rain Ready Ottawa home assessment, or
- Be working with a certified Fusion Landscape Professional, or
- For a permeable pavement project, be working with a certified Concrete Masonry and Hardscape Professional, or
- Have completed the relevant Rain Ready Ottawa eLearning courses.
That third option is the useful one for a paving job. If your contractor holds the Concrete Masonry and Hardscape Professional certification, you can qualify for a permeable pavement rebate without booking a home assessment first — which takes a step and a wait out of the process.
It is not retroactive. Your application has to be submitted and approved before construction starts. Work already done, or invoices predating the program approval date, are not eligible. Every year somebody builds first and asks second.
It is first-come, first-served. Rebates are limited and available on a first-come, first-served basis for eligible households, so the funding for a given year can run out. Applying early in the season matters.
Full guide to the Rain Ready Ottawa rebate → · Eligibility pre-check →
What it costs, honestly
Permeable costs more than conventional interlock to build. The pavers themselves are comparable, but the base is deeper, the aggregate is washed open-graded stone rather than ordinary granular, and the excavation and disposal go with it. Expect a premium over the $18–30 per square foot conventional range.
Which is exactly why the rebate matters. On a 300 square foot widening, a $5,000 rebate can more than cover the difference between conventional and permeable, and sometimes most of the total. Off the rebate, permeable is a drainage decision. On the rebate, it is often the cheaper finished driveway.
Permeable paver cost breakdown →
Where it doesn't work
We would rather tell you this now than after the excavation:
- Heavy clay with nowhere to go. Much of Ottawa sits on clay that drains slowly. Permeable still works — the base becomes storage rather than infiltration — but the design has to account for it, and sometimes an underdrain is needed.
- High water table or shallow bedrock. Limits how deep the storage can go.
- Steep slopes. Water runs across the surface faster than it soaks in.
- Close to a foundation with no separation. Infiltrating water beside a basement wall is the opposite of the goal.
Maintenance, which is real
The joints have to stay clean to keep working. Fines, leaf litter and lawn clippings gradually clog the surface, and a permeable driveway that has silted up is just a slightly odd-looking conventional one. Plan on periodic vacuuming of the joints, keep sand off it in winter, and don't let landscaping wash soil across it.
Find out if your address qualifies
Eligibility depends on which stormwater catchment you sit in, so two houses on a street can differ. We'll help you check before you plan around it.