Catch Basin Installation

Planning and site assessment for a driveway catch basin in the GTA

Planning and site assessment for a driveway catch basin in the GTA starts with understanding how water moves across your property and where it can safely discharge. For a driveway, a catch basin collects surface runoff at the low point and conveys it by gravity through a connected drain pipe to an approved discharge point such as a French drain, a dry well, or a municipal storm system connection, where allowed. Before digging, confirm the discharge path and ensure a consistent downhill grade from the basin to the discharge location.

What a driveway installation entails

• Identify the collection point: the lowest section of the driveway or where water consistently pools. In sloped driveways, this is often near the garage threshold or at the apron near the sidewalk/road.
• Plan the conveyance: lay out a straight, consistently sloped pipe run from the catch basin to the discharge point. Typical residential systems use 4-inch PVC pipes or PVC sewer pipes for durability and smooth flow.
• Choose integration: connect the catch basin to a French drain or a dry well if a municipal storm tie-in isn’t available. Where a municipal storm connection is proposed, verify that the municipality permits private property connections and what approvals are required.

When to hire a professional and permit cues

• Hire a pro when the basin/pipe alignment crosses utilities, when tying into a municipal storm structure, when traffic-rated components are required in the driveway, or when existing settlement indicates subgrade issues. Catch basin work is best performed by experienced drainage contractors to ensure proper grade, bedding, and long-term performance.
• Permits and inspections: check with your local building department before you start. In Toronto and neighboring municipalities, some replacements and many new installations—especially those tying to municipal infrastructure—may require permits and a final inspection.
• Municipal requirements vary by town: each GTA municipality sets its own rules for storm connections, lot drainage, and private tie-ins. Confirm current requirements with the local authority before finalizing your design.

Sizing, slope, and integration options

• Basin dimensions: common residential catch basin sizes range from about 6 to 18 inches. Select size based on contributing area, expected runoff, and surface loading from vehicles.
• Pipe size and slope: 4-inch PVC is typical for residential runs. Maintain a minimum 1% slope (about 1 inch fall per 8 feet of pipe). Where site constraints allow, 1%–2% helps keep sediment moving without excessive velocity.
• Bedding and cover: set the basin on 2–4 inches of compacted gravel. Provide 2–3 inches of bedding in the trench for the pipe run. Typical residential trenches maintain about 12–18 inches of cover above the pipe, adjusted to site conditions and local code.
• Sediment management: configure the outlet elevation in the basin slightly above the basin floor to create a sump that traps heavier debris and sediment, reducing downstream clogging.

Interior vs. exterior placement

• Exterior catch basins are the standard for driveway and yard drainage, capturing surface runoff before it reaches the house. They pair readily with French drains or dry wells where municipal tie-ins aren’t available.
• Interior drainage features are considered when the goal is managing water that has already reached the foundation or slab area, or where gravity discharge from outside isn’t feasible. Interior options and accessory devices are project-specific and subject to permit and code review; discuss these with your contractor and local building department.

Driveway-specific planning notes

• Traffic loading: choose components rated for vehicle loads in drive lanes and parking areas.
• Surface grading: ensure surrounding hardscape and landscape grades continue to shed water toward the basin and not toward the foundation.
• Seasonal performance: GTA freeze–thaw and heavy rain events demand consistent slope, proper bedding, and compaction to prevent settlement and icing around collection points.
• Weep Holes and hardscapes: if retaining walls with Weep Holes drain toward the driveway, confirm that flow paths are directed to the catch basin or a swale to prevent localized pooling.

Recommended dimensions and slopes (summary for planning)

• Catch basin: select from approximately 6"–18" classes based on area and load.
• Pipe: 4-inch PVC pipes/PVC sewer pipes are typical for residential drainage runs.
• Slope: minimum 1% from basin to discharge; 1%–2% preferred where practical.
• Bedding: 2–4 inches of gravel under the basin; 2–3 inches of bedding in the trench.
• Cover: plan for about 12–18 inches of soil cover over the pipe run, adjusted to site conditions and local code.

Planning checklist for GTA sites

• Confirm problem areas: document ponding spots on the driveway after rain.
• Choose your discharge: municipal storm tie-in (if permitted), French drain, or dry well.
• Verify approvals: contact your local municipality for permit/inspection needs and allowable storm connections; requirements vary by town.
• Map utilities: locate underground services before trenching.
• Set elevations: stake the basin rim and downstream pipe inverts to achieve a continuous 1%–2% slope.
• Select materials: traffic-rated basin body and 4-inch PVC drain pipe with proper adapters; plan for gravel bedding and compaction.
• Plan sediment control: include a sump area inside the catch basin to capture debris.
• Coordinate hardscape: plan sawcuts and restoration so finished grades direct runoff to the basin without creating trip lips or ponding.
• Maintenance access: ensure the basin location allows safe access for periodic silt removal and cleaning.

Drainage options at a glance

• French drain: disperses collected water along a perforated, gravel-wrapped trench downstream of the catch basin.
• Dry well: stores runoff temporarily and allows infiltration where soils permit.
• Municipal tie-in: where allowed by the municipality and code, directs flow to the public storm system.

Note: Municipal responsibilities and bylaws vary across the GTA. Always confirm current requirements with your local municipality before proceeding, and consult a qualified contractor for driveway installations that must withstand vehicle loads and freeze–thaw cycles.

A well-planned catch basin or trench drain setup protects GTA properties from pooling, freeze-thaw damage, and pavement deterioration by capturing runoff at the surface and moving it safely to a discharge point. Catch basins trap sediment below the outlet while trench drains collect sheet flow across driveways, walkways, and parking areas to prevent icing and slip hazards during winter thaws and heavy summer downpours.

Typical components and procurement

• Catch basin body and grate

- Basin (plastic or concrete) sized for the application; grate chosen for pedestrian/vehicle load where applicable. A sump area below the outlet traps grit and debris. In some yard applications, small weep holes at the basin bottom help the last bit of water drain off. Secure or encase as needed in concrete for driveways or traffic areas. [Installation often includes basin + pump + non‑return/check valve when gravity flow isn’t possible.]

• Pipes and fittings

- 4-inch PVC sewer/drain pipe and compatible fittings/adapters for inlet and outlet; solvent cement/primer or gaskets as specified by the basin manufacturer. Maintain consistent fall to the discharge point.

• Flow control and backflow components

- Non-return valve (check valve/backflow protection valve) on pumped or sensitive connections to prevent reverse flow or surcharge. An inverted T and airtight cover are common on interior tie-ins to manage air and maintenance access.

• Pumping equipment (when gravity drainage isn’t feasible)

- Sump/submersible pump in the basin or an exterior pumping station; high-water alarm; airtight cover. Provide a dedicated 110V power outlet and ensure exterior stations are buried deep enough to resist freezing.

• Bedding and anchoring materials

- Granular base (typically 2–4 inches) under the basin; sand/fine gravel bedding for pipe; site-appropriate backfill and compaction. Concrete collar or encasement around the basin and trench drain channels where load or buoyancy is a concern.

• Trench drain (when managing linear surface flow)

- Channel sections with end caps/outlets, compatible grates, and debris baskets. Select load class for expected traffic; typically set in concrete to maintain alignment.

• Tools and safety

- Trenching tools, level/laser for slope, tamper/plate compactor, saw for pipe, PVC cement/primer, silicone sealant, PPE (gloves, goggles). Always locate underground utilities before excavating and confirm required permits.

Basic installation flow (high level)

• Excavate basin hole and pipe trenches; prepare a level granular base for the basin.
• Set the basin, connect inlet/outlet pipes (maintain slope ~1% where feasible), install check valve and pump (if required), and place the grate just above finished grade.
• Test with water, then backfill/compact in lifts and complete surface restoration.

Why these components matter in the GTA

• Catch basins and trench drains help keep foundations, walkways, and pavement drier in heavy rain and freeze-thaw cycles. Basins capture debris to protect downstream lines; trench drains control sheet flow across hard surfaces, reducing winter ice build-up and extending pavement life.
• Exterior pumping stations and proper backflow/check valves are common where gravity discharge isn’t available or where municipal surcharge risk exists.

Procurement tips

• Confirm component compatibility (basin knockouts/adapters to 4-inch PVC), grate load rating for driveways/parking, and availability of alarms/airtight covers for interior systems.
• For commercial/driveway projects, specify grate/frame load class and concrete setting details.
• Municipal requirements and permits vary; check local rules before purchasing specialty components.

Financing, warranties, and quotes

• Financing and payment

- Ask bidders if they offer staged payments or financing; offerings vary by contractor. Get all terms in writing with milestones tied to excavation, rough-in, and final commissioning.

• Warranties

- Request written labour warranty and manufacturer documentation for pumps/controls. Many GTA plumbers advertise free estimates and fixed-rate pricing; 1-year labour warranties are commonly promoted—verify coverage, exclusions, and maintenance requirements.

• Quotes and permitting

- A professional quote should outline: basin/trench drain sizes and materials; pipe type/diameter and slope; bedding/encasement details; check/backflow valve placement; pump specs (if applicable) with power/alarm; restoration (asphalt, concrete, landscaping); and disposal of excavated material.

- Ask the contractor to confirm permit needs and inspection steps. Replacement or new tie-ins may require city permits; code compliance and final inspection should be included in the scope.

• Site visit checklist

- Provide photos, site grades, known utility locations, discharge options, traffic loading (pedestrian vs vehicle), winter maintenance constraints, and access for equipment. Professional installation is recommended—specialized tools, concrete setting, and proper testing reduce callbacks and flooding risk.

Step-by-step sequence

1) Plan and permissions

- Confirm your discharge point is an approved storm outlet. In Toronto, private storm catch basins are for storm/snowmelt only and connect to storm sewers, not sanitary lines, and must be installed to prevent accumulation and erosion per Municipal Code Chapter 681. Check permit and code requirements before digging.

2) Layout and elevations

- Choose the low point (yard low spot, driveway low point, or at a downspout). Establish continuous fall from the basin to the outlet. Maintain a minimum 1% slope from the basin to the discharge point.

3) Excavation

- Excavate the basin pit to allow for the basin depth plus a stable granular base (2–4 inches of gravel). Dig pipe trenches to maintain the designed slope, with about 12–18 inches of soil cover over the pipes where practical.

4) Base preparation and set the basin

- Place and level the gravel base. Set the catch basin so the finished grate will sit slightly proud of the surrounding surface (about 1/4 to 1/2 inch) to encourage runoff to enter and to avoid a depression at the grate.

- For driveway or parking lot applications, secure the basin with a concrete collar to protect against load and frost movement.

5) Pipe connections

- Knock out the appropriate inlets/outlet on the basin. Dry-fit then solvent-weld 4-inch PVC sewer pipes and fittings using PVC primer/cement; use gaskets or silicone sealant per the basin manufacturer’s details at the inlet/outlet.

- Maintain a consistent 1% fall on the outlet pipe run. Use an outlet pipe size matching the basin outlet (commonly 4-inch) to the approved discharge point.

- For gravity systems, install internal fittings as specified by the system (e.g., an inverted T inside the basin sump) and use an airtight cover where required to control odours.

- Where specified, include a non-return (check) valve or backflow protection valve on the discharge to prevent surcharge backflow.

6) Optional weep holes

- In stand-alone yard applications where slow drainage to surrounding soil is desired at the basin base, drill several small weep holes at the bottom of the basin to prevent residual pooling. Do not use weep holes when connecting directly to a storm sewer.

7) Backfill and surface restoration

- Backfill the trench and around the basin in layers, compacting as you go. Set the grate and finish the surface flush to surrounding grades (with the grate 1/4–1/2 inch higher, as above). In paved areas, reinstate concrete/asphalt after the concrete collar cures.

8) Testing and commissioning

- Hose-test the basin and line to verify continuous flow, confirm there are no leaks at joints, and that water does not back up at the grate.

Interior vs exterior configurations

• Gravity discharge (interior)

- Use gravity when the storm outlet is at least about 14 inches lower than the slab top/elevation at the basin. A typical package includes a catch basin, a check valve, an inverted T, and an airtight cover. Ideal where site elevations allow true gravity flow.

• Interior with submersible sump pump

- Choose this when the outlet elevation is higher than the basin invert and gravity is not feasible. Install a sump pump inside the catch basin or a dedicated sump pit; include a check valve on the discharge and an airtight cover.

• Exterior pumping station

- When interior placement isn’t practical, install an exterior pump station (concrete or plastic). It must be buried deep enough to resist freezing in the GTA climate and includes a pump, discharge line with check valve, and an alarm. Electrical work for alarms/power may require a licensed electrician.

• Backup pump option

- Add a battery-powered backup submersible pump to provide 24–48 hours of protection during power outages.

• Gravity with exterior storm connection

- Where the municipal storm is lower than your system and interior placement isn’t feasible, connect by gravity to the exterior storm line. Be aware this configuration can complicate thorough cleaning of upstream lines; plan cleanouts accordingly.

Toronto/GTA-specific notes

• Private storm catch basins are intended for stormwater only and typically connect to storm sewers; do not tie into sanitary. Installations should prevent stormwater accumulation and adverse impacts to adjacent properties, consistent with Toronto Municipal Code Chapter 681.
• Exterior pump stations must be set below the local frost zone and protected against freeze-thaw effects typical of GTA seasons.

Electrical and backup power considerations

• Provide a nearby 110V power outlet for any planned sump pump location; interior placements are often selected along an exterior foundation wall near power access.
• Install a non-return/check valve on all pumped discharges to prevent recirculation and short cycling.
• Where municipal storm lines may surcharge during extreme weather, add a backflow protection valve on the storm connection as specified.
• Exterior pump stations typically include an alarm; electrical components and alarm wiring should be installed by an electrician as required. For resilience during outages, specify a battery-backed sump pump rated for 24–48 hours of runtime.

Materials callout commonly used in GTA residential installs

• Catch basin with grates, airtight cover as specified
• 4-inch PVC sewer pipes and fittings, outlet pipe to approved discharge
• Check valve/non-return valve and backflow protection valve (as specified)
• Inverted T fitting (gravity systems)
• Gravel for bedding and backfill
• Sump pump (primary and optional backup)
• 110V power outlet and alarm components

A properly planned system treats the catch basin as the hub: water enters at grade and leaves through an outlet pipe into the broader drainage network. For most GTA residential installs, the outlet is tied to 4-inch PVC sewer pipes set on a steady decline toward a safe discharge point. The outlet opening is set slightly above the basin floor so the sump can trap grit before water enters the drain pipe, helping protect downstream infrastructure. In Toronto, stormwater from private systems must discharge to approved storm outlets and must not be tied into the sanitary sewer.

Integration with other drainage options

• Municipal storm drain/storm sewer connection

- What it is: The basin’s outlet pipe connects to the municipal storm system (not the sanitary line). A catch basin is a component that feeds storm infrastructure; it is not the same as the roadway storm drain network itself.

- When it fits: Properties with an available storm lateral or planned storm service. Typical residential laterals use 4-inch PVC pipes solvent-welded with primer/cement and laid to a consistent minimum slope (about 1% grade) to keep flow moving.

- GTA notes: In Toronto, connections are storm-only and subject to City rules; licensed contractors often assist with permits and approvals for private storm catch basins.

• French drain (perforated drain field) tie-in

- What it is: A long trench with perforated pipe wrapped in gravel that intercepts sheet flow or groundwater over a wide area. It disperses flow and can also convey water down-gradient.

- How to integrate: Use a solid 4-inch PVC outlet pipe from the catch basin to the French drain header so captured debris stays in the basin sump, not in the perforated run. The French drain section itself remains perforated and wrapped in aggregate; maintain a continuous decline away from structures.

- When it fits: Yards with broad, diffuse runoff or soggy low spots where point collection alone isn’t enough.

• Dry well discharge

- What it is: A subsurface storage pit that slowly releases water into surrounding soil through gravel or porous walls.

- How to integrate: Run a solid 4-inch PVC outlet pipe from the basin to the dry well, with the pipe sloped consistently. The basin pre-screens sediment so the well doesn’t clog as quickly.

- When it fits: Sites without a municipal storm tie-in where local grading and soil conditions allow infiltration and where discharging on-site is permitted.

• Surface “daylight” with emitter

- What it is: The outlet pipe terminates at grade on your property (often via a pop-up emitter) so water can safely release away from foundations.

- How to integrate: Continue the 4-inch PVC outlet to a safe point on a decline, maintain slope, and protect the termination with proper surface grading and gravel to avoid erosion.

- When it fits: Lots with enough fall to move water away from structures and property lines where municipal tie-in or infiltration aren’t suitable.

Quick comparison

• Catch basin vs. French drain: A catch basin is a point collector with a sump and outlet pipe; a French drain is a linear, perforated system that manages water across an area. They can work together when a point inlet needs to distribute flow along a trench.
• Catch basin vs. storm drain: The basin is a component on private property; a storm drain is the municipal network along roads and in the right-of-way. Private basins may connect to that network where allowed.
• Catch basin vs. dry well: The basin collects and conveys; the dry well stores and infiltrates. A basin often feeds a dry well to pre-screen debris and extend the well’s service life.

Key connection practices

• Use solid-wall 4-inch PVC sewer pipes for outlet runs; reserve perforated pipe for French drains only.
• Maintain a consistent fall from the basin to the discharge point to prevent standing water in the line.
• Keep the outlet pipe connection watertight and ensure the sump remains below the outlet to trap sediment before it reaches downstream systems.

Backfilling and compaction

Done right, backfilling and compaction keep a new catch basin stable through GTA freeze–thaw cycles and heavy downpours. The goals are to lock the basin in place, support the frame and grates, shed surface water properly, and avoid future settlement.

• Stabilize the basin before you start: Where durability or traffic loading is expected (driveways, parking stalls, laneways), set or collar the catch basin in concrete to protect the structure and extend its lifespan. This also helps resist movement in saturated soils after major storms. In lawn or garden settings, a compacted granular surround is typically sufficient, but a small concrete collar at the frame may still be used for edge support around the grate.
• Bedding that drains: Place the basin on a level granular base (clean gravel) so it seats flat and doesn’t rock. A gravel base also makes it easier to get the grate to finish at the correct height.
• Final grate height: In turf or garden areas, set grates slightly proud of finished grade (about 1/4–1/2 inch) so water can find the inlet and sod doesn’t overgrow it. In paved areas, finish the grate flush with the asphalt, pavers, or concrete so it doesn’t become a trip hazard or a plow/snowblower catch point.
• For airtight cover configurations: If your catch basin uses an airtight cover (common on sealed or interior-style setups), keep the lid and sealing surfaces clean during backfill, don’t encase the lid in concrete, and ensure the cover can be removed and reseated without binding. Protect the cover from compaction equipment and confirm the seal seats evenly all around when closed.
• Compact in thin lifts: Backfill evenly on all sides of the basin in thin layers, compacting gently as you go. Use a hand tamper close to the basin walls to avoid shifting it, and a small plate compactor a bit farther out where there’s room. Avoid dumping large amounts of soil on one side, which can rack the structure.
• Choose suitable backfill: Use free‑draining granular material (gravel/sand) immediately around the basin to reduce water pressure and frost jacking; native soils can be used farther out if placed in thin lifts and compacted well. More gravel around the structure improves drainage and reduces settlement.
• Traffic-rated support: Where the catch basin will see vehicle loads, verify the grate and frame are the correct load class and ensure the surrounding base, collar, and pavement restoration match the traffic demand. Proper compaction under and around the frame prevents cracking, rocking grates, and potholing.

Backfill materials and compaction steps

1) Prepare and bed the basin

• Place and level a compacted gravel base under the catch basin. Confirm the basin is plumb and stable before proceeding.

2) Secure the structure

• If required, pour a concrete collar around the basin body or frame area to protect the structure and provide long-term support, especially in driveways and parking areas. Allow adequate cure before heavy compaction nearby.

3) Build up in layers

• Place free‑draining granular around the basin first, working evenly on all sides. Compact gently in thin layers with a hand tamper near the walls, then transition to a plate compactor as you move outward.

4) Set final elevations

• Shape the surface so the grate is slightly higher than surrounding turf or flush with hardscape, as applicable. Ensure positive surface flow to the inlet with no low spots that could ice over in winter.

5) QA checks before closing the site

• Stability: Press on the basin and frame; there should be no rocking.
• Grate/cover seating: Confirm the grates or airtight cover sit level, seat properly, and can be removed/reinstalled without binding.
• Flow test: Run a hose into the grate to confirm water enters freely and doesn’t pond around the structure. Re‑check after the first heavy rain for any settlement and top up surface material if needed.

When to bring in a professional

• Driveways, laneways, or parking areas: Traffic-rated grates, proper concrete collars, and compaction around pavement require contractor tools and experience to meet load and durability needs.
• Signs of high groundwater or saturated soils: Added measures like concrete securing and staged compaction are often needed to prevent movement after storms.
• Code/inspection requirements: Some replacements and municipal tie‑ins involve permits and final inspections; a licensed contractor will handle compliance and documentation.
• If you can’t achieve stable compaction in layers or the basin won’t stay plumb: A pro can re‑bed, re‑collar, and reset elevations so grates and covers perform correctly through GTA freeze–thaw cycles.

Handover, testing, and maintenance

Before handover in the GTA, a new catch basin needs a controlled water test and a documented commissioning to confirm it captures surface runoff, moves it through the drain pipe to the approved discharge, and, where applicable, cycles the sump pump reliably. The goal is to prove flow paths, check for leaks, and verify the installation will stand up to our quick swings from heavy rain to snowmelt.

Functional testing checklist

• Pre-test verification

- Compare the installed catch basin, outlet elevation, and drain pipe routing against the approved plan or sketch. Confirm the discharge point is permitted by your municipality.

- Ensure the inlet opening is set to receive water from surrounding grades (no high edges that would shed water away).

- Remove construction debris from the basin and confirm the sump is clear so sediment can settle below the outlet level.

• Controlled water test (gravity systems)

- Introduce water steadily at the surface inlet and observe that it enters the catch basin without bypassing.

- Confirm continuous flow through the drain pipe toward the discharge point. Watch for any backup or slow drawdown once the water source is shut off.

- Inspect visible joints and connections for leaks while water is flowing. If accessible, check downstream for confirmed discharge.

- Hose-test the surrounding surface to verify positive drainage into the basin and no unintended ponding nearby.

• Pumped systems (where a sump pump is installed)

- Add water until the pump float activates. Verify the sump pump starts, moves water through the discharge pipe, and stops at the proper low-water level.

- Confirm any alarm (if included) functions when the float is lifted to the alarm set-point.

- For exterior pump stations, confirm the chamber is buried to resist freezing and all penetrations are sealed.

• Final checks

- Reconfirm inlet elevation relative to paving/soil after compaction and restoration.

- Record pass/fail notes, times to drain down, and any deficiencies for correction before backfill restoration is finalized.

Commissioning protocol

1) Document review and visual inspection

• Verify municipal approval/permit conditions (if applicable) and that the catch basin, drain pipe sizes/routes, and discharge match the design intent.
• Inspect the basin body and connections for damage, settlement, or misalignment.

2) Static leak and drawdown check

• Partially fill the catch basin to just above the outlet elevation and observe for a steady drawdown. Check all accessible joints for leaks. Water should not back up in the basin once the source is removed.

3) Dynamic flow verification

• Run a hose at a moderate, continuous rate into the surface inlet to simulate a rainfall event. Confirm uninterrupted conveyance through the drain pipe and visible discharge at an accessible downstream point. Verify no surface ponding adjacent to the basin.

4) Sump pump commissioning (if installed)

• Wet-test the pump cycle: note the start and stop levels, listen for abnormal noise/vibration, and verify discharge is clear and steady. Confirm alarm operation (if provided). Restore the basin to normal water level.

5) Optional internal inspection

• For longer or critical runs, perform a camera (CCTV-style) inspection of the drain pipe to confirm clean, continuous slope and intact joints before final acceptance.

6) Handover and maintenance setup

• Provide the owner with commissioning notes (test dates, results, photos), the as-built discharge location, and a maintenance schedule. At minimum, plan debris/silt removal from the basin sump seasonally and after major storms, and an annual inspection of connections.

7) Final acceptance

• Where a permit or jurisdictional sign-off is required, schedule the final inspection and retain approval records with the project file.

FAQ

• What is a catch basin and why is it used on a GTA driveway?

- A catch basin is a point-collection device that traps debris and directs runoff into a discharge pipe, preventing ponding and protecting downstream systems.

• What pipe size and slope are typical for residential driveways?

- Most residential runs use 4-inch PVC with a minimum slope of 1% (1 inch per 8 feet), with 1–2% preferred when feasible.

• Do I need a permit for GTA catch basin installation?

- Permitting varies by municipality; many GTA areas require permits or inspections for private storm connections or tie-ins to municipal systems.

• Should I hire a professional or can I do it myself?

- For driveways and vehicle loads, professional installation is advised to ensure proper grade, bedding, and durability against freeze–thaw cycles.

• What is interior vs exterior placement?

- Exterior basins handle surface runoff on the outside of the building; interior systems manage water within or near the foundation and may require pumps or airtight access.

• How is backfill and compaction done?

- Backfill in thin layers with gradual compaction, using free-draining granular material around the basin and a concrete collar when driveways are involved.

Short description

A practical guide to planning, sizing, installing, and commissioning a driveway catch basin in the GTA, covering grading, piping, pumping options, permits, backfill, and testing.