Understanding Trenchless Sewer Repair

Traditional sewer line repair or replacement involves excavating a trench from one end of the failed pipe section to the other — often running 20 to 30 metres or more from the house foundation to the property line or the municipal main. This means digging up lawns, gardens, concrete driveways, interlocking brick, and sometimes even portions of the road allowance. The excavated material must be stockpiled, the old pipe removed, new pipe bedded and installed, and the trench backfilled and compacted in layers. Surface restoration — resodding, repaving, replanting — adds additional cost and time.

Trenchless sewer repair replaces most of this process with techniques that work from inside the existing pipe or from small access pits at the ends. The host pipe's existing path through the ground serves as the access channel, eliminating the need to excavate the entire run. The result is a repaired or replaced pipe with far less disruption to the property, the neighbourhood, and the homeowner's daily life.

The Three Main Trenchless Sewer Repair Methods

1. CIPP Lining (Cured-In-Place Pipe)

CIPP lining inserts a resin-saturated flexible liner into the existing damaged pipe. The liner is cured (hardened) in place using hot water, steam, or UV light, forming a smooth, jointless new pipe inside the old one. CIPP is ideal for cracked, root-infiltrated, or corroded pipes that retain their basic shape and can structurally support the liner during insertion. It leaves the original pipe shell in place as a casing around the new liner. CIPP does not increase the pipe's outside diameter, making it particularly useful when the existing pipe runs close to other utilities or structures.

2. Pipe Bursting

Pipe bursting is used when the existing pipe needs to be replaced rather than rehabilitated — for example, when it is completely collapsed, severely crushed, or has multiple offset joints. A cone-shaped bursting head is pulled through the existing pipe by a hydraulic pulling machine. As the bursting head travels through the pipe, it fractures and pushes the old pipe material outward into the surrounding soil. Simultaneously, a new high-density polyethylene (HDPE) pipe is pulled in behind the bursting head, replacing the old pipe in one pass. Pipe bursting can also upsize the replacement pipe to a larger diameter — a useful option if flow capacity needs to be increased.

3. Slip Lining

Slip lining involves inserting a continuous or segmental new pipe of slightly smaller diameter into the existing host pipe. The annular space between the new pipe and the old pipe is then grouted to provide structural support. Slip lining is less common in residential applications because it results in a meaningful reduction in internal pipe diameter. It is more frequently used for larger-diameter municipal infrastructure where some flow capacity reduction is acceptable and speed of installation is prioritized.

Method	Best For	Excavation	Diameter Change
CIPP Lining	Cracked, root-invaded, corroded pipes	Access pits only	Slight reduction (6–10mm)
Pipe Bursting	Collapsed or severely damaged pipes	Entry/exit pits	Same or larger
Slip Lining	Large-diameter municipal pipe	Access pits only	Reduced

How Trenchless Sewer Repair Begins

Every trenchless sewer repair project starts with a thorough CCTV camera inspection of the affected pipe. The inspection footage allows the plumber to assess pipe condition, identify the type and extent of damage, measure the pipe diameter and length, locate laterals connecting to the main line, and determine which trenchless method is appropriate. Attempting trenchless repair without a camera inspection risks choosing the wrong technique for the pipe's condition — potentially wasting money or causing additional damage.

Following inspection, the pipe is cleaned using hydro jetting to remove debris, roots, scale, and grease. Clean pipe walls are essential for CIPP liner adhesion. For pipe bursting, cleaning ensures the bursting head can travel unobstructed through the pipe interior.

Trenchless vs. Traditional Open-Cut: When to Choose Each

Trenchless methods are appropriate for the majority of residential sewer lateral rehabilitations in Ontario, particularly in properties with mature landscaping, concrete driveways, or structures built close to the pipe line. However, open-cut replacement remains the necessary approach in some situations:

• Complete pipe collapse: A fully collapsed pipe cannot be cleaned or used as a guide path for trenchless equipment. Partial excavation or full open-cut replacement is required.
• Major grade correction: If the existing pipe has settled and lost its proper slope toward the sewer main, the grade cannot be corrected by lining or bursting without repositioning the pipe — which requires excavation.
• Very short pipe sections: For very short failures — a one- or two-metre section with a broken joint — spot excavation and direct repair may be faster and more economical than mobilizing full trenchless equipment.
• Extreme bellying: A severely sagged pipe section that holds standing water cannot be corrected by lining. Bursting or open-cut replacement that re-establishes proper drainage slope is needed.

Cost of Trenchless Sewer Repair in Ontario

Trenchless sewer repair costs in Ontario vary significantly based on method, pipe length, diameter, and local conditions. General ranges for residential sewer lateral work:

• CIPP lining: $80–$250 per linear foot; $5,000–$15,000 for a typical 20–40 metre residential lateral
• Pipe bursting: $100–$250 per linear foot; $6,000–$20,000 for a typical residential lateral with new HDPE pipe
• Camera inspection (pre and post): $150–$350 per inspection, typically included in a full-service trenchless quote
• Hydro jetting (pre-cleaning): $300–$800, often included in a bundled trenchless service quote

While the per-foot material cost for trenchless methods may exceed that of conventionally placed pipe, the total project cost — including excavation, equipment mobilization, surface restoration, and time — often makes trenchless methods comparable or less expensive than open-cut. A property with a mature tree over the sewer line, an interlock driveway, or a finished basement with floor drains can face restoration costs that make open-cut far more expensive in practice.

Durability and Lifespan

Both primary residential trenchless methods produce long-lasting results. CIPP liners installed to ASTM F1216 specifications are designed for a 50-year service life. HDPE pipe used in pipe bursting applications carries a design life of 50 to 100 years and is highly resistant to corrosion, root intrusion, and ground movement. These durability profiles are comparable to or exceed those of traditionally placed PVC or clay tile pipe.

The smooth interior of both CIPP liners and HDPE pipe reduces the likelihood of future root infiltration and grease accumulation, potentially reducing the frequency of future drain cleaning service calls.

Impact on Landscaping and Property

One of the most valued advantages of trenchless sewer repair for Ontario homeowners is the minimal impact on their property. Because no trench is dug along the pipe route, the following are preserved:

• Established trees, gardens, and perennial plantings above the sewer line
• Concrete or interlocking brick driveways and walkways
• Pool decks, patios, and hardscaping
• Interior finished spaces in the case of under-slab pipe
• Boulevard trees in municipal right-of-way areas

The two small access pits required for pipe bursting — one at each end of the pipe section — are typically 1 to 1.5 square metres in size and can be backfilled and restored within one to two days. The restoration cost for these small pits is a fraction of the cost to restore a full-length trench.