Pipe Bursting in National City

National City was incorporated in 1887, second in the county only to San Diego itself, and much of its housing stock dates from the 1900s through the 1950s. The grid between National City Boulevard and Highland Avenue is packed with early bungalows, craftsman cottages, and postwar stucco houses on narrow lots, many with a second unit in back. Brick Row and the Kimball-era blocks in Old Town are older still. The west side, from the freeway to the bay, is built on fill over what was once tidal marsh.

That combination of age, density, and wet ground is why trenchless sewer repair has become the sensible default here. Open trenching on a 40-foot-wide lot means tearing out the driveway, the walkway, and often the neighbor's fence line; on the bayfront it means pumping groundwater out of the hole. Lining or bursting from a cleanout keeps the disturbance to a pit the size of a card table. National City is covered by the trenchless crews serving San Diego County; what follows is particular to this city.

What the old pipes are made of

From the 1900s through the 1950s, the lateral material was vitrified clay in short lengths with mortar joints, transitioning to cast iron inside the foundation wall. On a raised-floor bungalow, the cast iron is often the first thing to fail, scaling inside until a two-inch channel is all that remains. Outside, the clay joints open under root pressure from the ficus, camphor, and pepper trees that line the older streets, and the parkway palms that look harmless send out fine roots that mat inside the pipe.

Lots that were re-plumbed or built in the late 1940s through the 1960s may carry Orangeburg, the compressed fiber pipe that softens and ovalizes over time. Postwar tracts in the eastern part of the city near Paradise Hills and Lincoln Acres were more likely to get clay again, sometimes with early rubber gaskets. The soil across most of the city is clay-rich and holds water, while the west side's fill is a loose mix of sand and dredge spoil with groundwater only a few feet down.

Multi-unit and mixed-use buildings are common along the Highland Avenue and 8th Street corridors. These often share one lateral among a storefront and several apartments, with a long cast iron run under the slab and a clay segment to the street. Grease from commercial kitchens and decades of scale narrow those lines steadily.

Which trenchless method suits which defect

Nothing is proposed until the line has been hydro jetted and a camera has recorded its full length with footage marks and a surface locate.

• CIPP lining is the workhorse for clay laterals with leaking joints and root intrusion where the pipe still holds its shape. A resin-saturated tube is pulled or inverted through and cured into a seamless pipe that stops infiltration as well as roots. The learn how CIPP liners are installed covers the resin systems and cure methods.
• Pipe bursting replaces collapsed clay, flattened Orangeburg, or an undersized lateral by fracturing the old pipe and drawing new HDPE through the same path from two small pits, which matters on lots with no room for a trench.
• Sectional point repair fixes a single broken joint or a short offset in a lateral that is otherwise sound, and is useful at a sharp fitting a full liner cannot pass.
• Spin-cast lining restores the larger cast iron and concrete building drains under commercial and apartment buildings, applying a centrifugal coating that rebuilds wall thickness.

On a mixed-use building the job may combine spin-cast under the slab with a felt liner on the clay segment to the main. What the camera records, and how it shapes the repair plan, is explained in how the camera inspection works.

Permits, locating, and the right-of-way

National City is an incorporated city, so the plumbing permit and the encroachment permit for any work under the sidewalk or street are issued by the city, and the city engineering staff inspect the connection to the main. Unincorporated Lincoln Acres, which is surrounded by the city, falls under County of San Diego Planning and Development Services instead. DigAlert, the regional 811 service, must mark gas, water, and communication lines before any pit is dug, and on the dense older blocks those lines are close together.

Under the city's rules, as in most local agencies, the property owner maintains the lateral all the way to the main, including the segment under the public right-of-way. There is no citywide point-of-sale sewer inspection, but with so much housing over a century old, buyers and lenders routinely ask for a camera report, and a documented lining job settles the question.

What to expect from the estimate visit

A licensed trenchless contractor will locate a cleanout, jet the line, and record a camera inspection while a locator traces the route across the lot. On a multi-unit property, expect questions about tenant access and water shutoff windows. The written scope should name the method, the access points, the permits, and the restoration of concrete or landscaping. Keep the video as your baseline.

Pipe Bursting in National City

How pipe bursting works

A steel cable is threaded through the old sewer line from a pit at one end to a pit at the other. A cone-shaped bursting head, with new high-density polyethylene pipe fused to it, is pulled through by a hydraulic unit. The head splits the old clay or cast iron outward into the soil and the new pipe follows in the same alignment at the same depth. The result is a single fused length of pipe with no joints for roots to find.

When bursting is the right call

• Collapsed sections — a liner needs a host pipe to hold its shape; a collapsed run has none.
• Bellies — a low spot that holds water stays a low spot after lining. Bursting lays new pipe on a fresh bed.
• Undersized lines — bursting can upsize a 3-inch lateral to 4 inches; lining slightly reduces diameter.
• Badly deformed pipe — Orangeburg that has flattened, or cast iron with most of its bottom gone.

What the job looks like

One pit at the house or cleanout, one at the property line or the street connection, each a few feet square. Utilities that cross within a foot or two of the sewer path are located and potholed first. The pull takes an hour or two; the whole job, including fusing, connections, inspection and backfill, is usually one day.

Permits and the street

If the downstream pit is in the sidewalk, parkway or street, a right-of-way permit and restoration to city standards are required in addition to the plumbing permit. If the connection at the main is replaced, the city inspects it before the pit closes. Confirm who is handling this before work starts.

More trenchless services in National City

Questions we hear in National City