Not every sewer problem is in the yard. Sometimes the failing pipe is under your floor.
Written byNew Pro Plumbing·Reviewed byMiguel Lopez, Owner & Licensed Plumber, New Pro Plumbing (CSLB #974600)·Last reviewedSeptember 2026 · 8 min readQuick Answer
The building drain, the part of the sewer that runs under the house, can crack, corrode, or separate just like the lateral outside. In a raised-foundation home it's often reachable from the crawlspace; under a slab, lining from a cleanout can often avoid breaking the floor. In Mar Vista, many older homes have raised foundations, so the building drain is often reachable in the crawlspace.
Inside the foundation, your home's drains come together in a building drain that carries waste out to the lateral. In older homes it's often cast iron, which corrodes and cracks with age. In a raised-foundation home, that pipe runs through the crawlspace. In a slab home, it's buried beneath the concrete. This page is part of our complete guide to sewer line repair in Mar Vista.
Under-House Sewer Repair: Under-house sewer repair is the repair of a building's drain line beneath the home, in a crawlspace or under a slab foundation.
Crawlspace repairs are usually straightforward: we can reach the pipe and replace or repair the damaged section. Under a slab, the choice is between cutting the floor to reach the pipe and lining it from a cleanout. When the pipe qualifies, lining saves the floor.
In Mar Vista, many older homes have raised foundations, so the building drain is often reachable in the crawlspace. Raised foundations are common in older Mar Vista homes, giving direct crawlspace access to the drain.
We inspect the building drain from a cleanout or fixture.
We mark its position under the floor or in the crawlspace.
Direct repair in a crawlspace; lining or targeted access under a slab.
A final camera pass confirms the repaired line.
Camera first, always. Every recommendation starts with a recorded inspection you can watch yourself, and a flat-rate price you approve before we start.
Mar Vista's older homes are often built on raised foundations, which is good news for under-house sewer repairs. The cast-iron building drain runs through the crawlspace, and we can usually reach the damaged section directly without opening a floor. Postwar homes in parts of Mar Vista are more likely to be on slabs, and there the conversation shifts to lining: descaling the cast iron and installing a liner from a cleanout to avoid breaking the concrete. Either way, the camera comes first, so we know exactly where the problem is.
Most Mar Vista homes went up between the 1920s and the 1950s, and a lot of them still drain through the sewer lateral they were built with. Kitchen remodels and added bathrooms have pushed more flow through lines that were sized and laid for a smaller house. We explain what we find in plain English or Spanish, and we don't sell work the camera doesn't support.
Not sure what your line needs? We camera it first, then quote a flat rate.
Get a Free Quote| Detail | Mar Vista |
|---|---|
| Area | Mar Vista, CA 90066 |
| Jurisdiction | City of Los Angeles |
| Permits | LADBS (City of Los Angeles) |
| Typical access | A cleanout or fixture; targeted excavation only when needed |
| First step | Camera inspection with a copy of the recording |
| Pricing | Flat-rate, in writing, before work starts |
| Availability | 24/7, including weekends and holidays |
| License | CSLB #974600, insured |
| Languages | English and Spanish |
Mar Vista is inside the City of Los Angeles, so sewer work on private property is permitted and inspected through LADBS. The inspector checks the new pipe, the connections, and any cleanout before the job is closed out, which is the record you want at resale. We time the permit, the work, and the inspection so the line is out of service as briefly as possible.
Example scenario below is illustrative, based on common situations we see. Details vary by property; not a specific customer.
A 1930s Mar Vista home has a damp crawlspace and a faint sewer odor in the hallway.
We find a corroded, cracked cast-iron section in the crawlspace and replace it directly.
The crawlspace dries out, the odor disappears, and no flooring is disturbed.
New Pro Plumbing is family-owned and led by Miguel Lopez, and many Mar Vista customers ask for him by name. Permits and inspections are part of the job, and part of the price. Our goal is simple: fix it right once, so you don't have to call us back for the same problem.
Also serving neighborhoods near Mar Vista: Palms, Del Rey, Culver City, Westdale. See all Westside service areas.
The Bottom Line
When the failing pipe is under your home, the right tools can usually fix it without major demolition: direct repair in a crawlspace, or lining under a slab.
The camera tells us exactly where the damage is. Odors inside, a damp crawlspace, or slow drains throughout can point that way. Under-house sewer work usually means the cast-iron building drain in the crawlspace or under a slab. See our cast-iron corrosion page for the wear pattern.
Often not. Crawlspace lines can be reached directly, and under-slab lines can often be lined from a cleanout. For raised-foundation homes, we access the pipe from the crawlspace and either replace the failed section or descale and line it. Lining preserves the run without cutting more pipe than needed.
Older cast iron corrodes and cracks with age. It’s worth inspecting if your home is decades old. For slab-on-grade homes, opening a slab is invasive. Lining from a cleanout is often the practical fix and avoids demo in a finished room.
Yes, if the pipe is intact enough. We descale it first, then line it. Under-house work is a plumbing permit item. We pull it through LADBS in the City of LA or LA County Public Works for unincorporated areas.
Usually, yes. Many older Mar Vista homes have crawlspaces that let us reach the cast-iron building drain without opening floors. For Mar Vista raised-foundation homes, crawlspace access makes cast-iron work manageable without opening floors. See Mar Vista sewer repair hub.
This page was written by the New Pro Plumbing content team and reviewed for technical accuracy by Miguel Lopez, owner and California-licensed plumber (CSLB #974600). Agency rules are summarized from the official sources above; programs and requirements can change, so confirm current details with the agency. Nothing here is a quote. We confirm scope and pricing in writing before any work begins.
What’s new: September 2026, first publication.
Not every sewer problem is in the yard. Sometimes the failing pipe is under your floor.
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