A City Built on a Slope
Mission's geography sets it apart from every other Fraser Valley community we serve. The city rises from the Fraser River up a long south-facing slope, from the flats near the bridge through the older downtown grid and up through neighbourhoods that keep climbing toward Stave Falls and Steelhead. Rainfall increases with elevation, and upper Mission catches over 1,800 millimetres in a typical year, among the heaviest totals in the region.
On a slope, every property is part of a chain. Rain landing uphill travels down, over the surface during storms and through the soil for weeks afterward. Your foundation stands in that path. This is why Mission homes wrestle with problems that flatland homes rarely see: seasonal springs that appear mid-slope, saturated back yards cut into the hill, water arriving at the uphill wall of the basement while the downhill side stays dry, and retaining walls leaning under hydrostatic load.
The Older Housing Stock Makes It Harder
Mission's core neighbourhoods, the streets above and around downtown with their early and mid-1900s character homes, carry the oldest drainage infrastructure in our service area. Many of these homes have clay tile perimeter drains laid generations ago; some of the earliest have no perimeter drainage at all, just rubble backfill against stone or early concrete foundations. After decades of hillside silt and root pressure from mature trees, the tile systems that do exist are commonly packed solid.
For these homes we follow the evidence: a camera inspection establishes what exists and its condition, high pressure flushing restores systems that are intact, and replacement, with waterproofing while the wall is exposed, handles the ones that are done. On steep lots we plan machine access carefully, and where a spring line or heavy uphill flow is part of the picture, we say so and design for it rather than pretending the perimeter drain can do everything.
Intercepting the Hill
The signature Mission project is the uphill interceptor: a French drain cut across the slope above the house, catching descending groundwater and surface flow, and carrying it in solid pipe around the home to a safe downhill discharge. Paired with a swale for storm surface water and properly piped downspouts, an interceptor takes the uphill load off the perimeter drains entirely. Many chronic Mission wet basements are solved above the house, not beside it.
The Lowlands: Hatzic and the River Flats
Down at river level the problem inverts. Hatzic, the neighbourhoods along the Lougheed corridor east of the bridge, and the flats toward Dewdney sit on floodplain silt with a winter water table just below the surface. These homes need what flatland homes across the valley need: clear, flowing perimeter drains, roof water piped well away, and very often a sump pit with a battery-backed pump to provide the lift the flat ground cannot.
Drainage Services in Mission
- Perimeter Drain Replacement: Full excavation and replacement of failed clay tile or collapsed drain lines with modern PVC perimeter drainage.
- Perimeter Drain Cleaning & Flushing: High pressure flushing that clears silt, roots and debris from working drain tile, often for a fraction of replacement cost.
- Drain Camera Inspection: See exactly what is happening inside your perimeter drains before you spend a dollar on repairs.
- Sump Pump Installation: Sump pits and pumps for high water table properties where gravity drainage alone cannot keep up.
- Foundation Waterproofing: Membranes, dimple board and damp proofing applied while the foundation is exposed, so water never reaches the concrete.
- French Drains & Yard Drainage: Surface and subsurface drainage for soggy lawns, pooling driveways and hillside runoff that has nowhere to go.
- Downspout & Drainage Connections: Proper downspout tie-ins, storm connections and discharge lines that carry roof water well away from your foundation.
Nearby Communities
From Mission we also serve Abbotsford across the river, Langley to the southwest, and Maple Ridge, Deroche and Dewdney by arrangement.
Mission Drainage FAQs
Why is drainage different in Mission than in the rest of the valley?
Mission is a hillside city. Most of it climbs the south-facing slope above the Fraser River, so nearly every property both receives runoff from uphill and sheds water to the properties below. Add some of the heaviest rainfall in the valley, over 1,800 millimetres a year in the upper neighbourhoods, and managing moving water, not just standing water, becomes the core drainage job in Mission.
My older Mission home uphill from downtown gets water in the basement. Is that runoff or failed drains?
Very often it is both. The character homes in Mission’s older core commonly have clay tile drains from the mid-1900s that are silted or collapsed, and the same properties take concentrated runoff from the streets and lots above. A camera inspection separates the two causes, and the fix is frequently an uphill interceptor drain paired with flushing or replacing the perimeter system.
What about the flat areas like Hatzic and the lowlands?
The low-lying areas around Hatzic, along the Fraser and toward Dewdney sit on floodplain with a high winter water table, the same profile as the prairies across the river. Homes there lean on sump pumps, clear perimeter drains and properly discharged roof water, and battery backup pumps matter because outages ride in with the storms.
Do hillside springs really cause basement problems in Mission?
Yes. The Mission slope carries groundwater moving downhill through the soil year round, and it surfaces as springs and seeps, sometimes seasonally, sometimes permanently, occasionally appearing for the first time after uphill development changes the flow. A perimeter drain in the path of a spring line works hard all winter, and an interceptor drain uphill of the house is often the fix that actually solves it.
How much does drainage work cost in Mission?
Mission follows our regional pricing: camera inspections typically $300 to $600, flushing $600 to $1,500, full perimeter replacements commonly $15,000 to $30,000, and hillside interceptor drains from a few thousand dollars depending on length and access. Steep-lot access can affect excavation cost, which is exactly why we quote firm after a site visit.