If your drains slow down or back up after it rains, water is probably getting into your sewer line where it shouldn't.
Written byNew Pro Plumbing·Reviewed byMiguel Lopez, Owner & Licensed Plumber, New Pro Plumbing (CSLB #974600)·Last reviewedSeptember 2026 · 8 min readQuick Answer
Sewer problems after rain usually mean stormwater or groundwater is entering the sewer through cracks, open joints, damaged cleanouts, or improper connections, overloading the line. We camera the line to find the entry points and seal them. In Mar Vista, rain-related problems usually trace to cracked, root-opened clay joints and old, low cleanouts.
Sanitary sewers are designed to carry wastewater, not rain. When stormwater or rising groundwater gets into the line, through cracks, open joints, a broken cleanout, or a downspout or area drain connected where it shouldn't be, the extra water can overwhelm the pipe and cause slow drains or backups. This page is part of our complete guide to sewer line repair in Mar Vista.
Sewer Problems After Rain: Sewer problems after rain occur when stormwater or groundwater enters a sanitary sewer line through defects or improper connections and overloads it.
The EPA notes that sewer defects letting in stormwater and groundwater are one of the causes of sewer overflows. At the household level, the fix is finding the entry points. A camera inspection shows cracks and open joints, and a site check finds any improper connections.
In Mar Vista, rain-related problems usually trace to cracked, root-opened clay joints and old, low cleanouts. Root-opened clay joints in Mar Vista laterals can take in water during storms.
We look for downspouts, area drains, or sump lines tied into the sewer.
Broken or uncapped cleanouts can take in surface water.
We look for cracks and open joints letting water in.
Repair, line, or reroute, depending on the source.
Camera first, always. Every recommendation starts with a recorded inspection you can watch yourself, and a flat-rate price you approve before we start.
Wet-weather sewer problems in Mar Vista usually trace to the same old clay laterals that cause so many other issues. Joints opened by roots let groundwater in when the soil saturates, and old cleanouts in low spots of the yard can take in runoff. We also occasionally find older properties where a downspout or area drain was tied into the sewer decades ago. We check connections and cleanouts, camera the line to find infiltration, and seal the entry points, often by lining the lateral.
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. Many laterals here have been patched once or twice over the years, so a single run can mix clay, cast iron, and newer plastic. We start with a camera so you can see the line yourself before anyone talks about price.
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. LA Sanitation has offered lateral rebates for CCTV inspection and for repair to qualifying owners who pay the City sewer service charge, while annual funds last, so it's worth checking before you start. We'll tell you up front if your job needs anything beyond a standard plumbing permit.
Example scenario below is illustrative, based on common situations we see. Details vary by property; not a specific customer.
A Mar Vista homeowner's shower backs up only during heavy rain.
We find a low, cracked cleanout taking in runoff and open clay joints letting in groundwater.
We rebuild the cleanout and line the lateral, and the rain-related backups stop.
New Pro Plumbing is family-owned and led by Miguel Lopez, and many Mar Vista customers ask for him by name. Our trucks carry the camera, locating, jetting, and repair equipment most sewer jobs need. And when we leave, we leave no trace behind.
Also serving neighborhoods near Mar Vista: Venice, Santa Monica, Westside Village, Palms. See all Westside service areas.
The Bottom Line
Rain shouldn't affect your sewer. If it does, water is getting in. We find the entry points on camera and seal them.
Rainwater or groundwater is likely getting into the line through defects or connections and overloading it. Sewer problems that appear only during or after rain point to infiltration: groundwater entering the sanitary sewer through cracks, joints, or improper connections. See the EPA’s page on sanitary sewer overflows.
It happens, especially in older properties. It’s generally not allowed and can overload the line. Downspouts or area drains illegally tied into the sanitary sewer are a common cause. That is a code violation in both the City of LA and unincorporated County.
Occasionally. That’s one reason some properties use backwater valves. We’ll help figure out whether the issue is your line or the main. The fix is sealing the entry points, usually by lining the lateral, and disconnecting any improper connections. See our sewer backup page for related symptoms.
Sealing cracks and joints with a liner or repair, fixing cleanouts, and removing improper connections. For a property with a history of rain-related backups, a backwater valve on the sewer service is worth considering as an added layer of protection.
It happens occasionally on older properties. It can overload the line during storms, and we check for it during inspection. For Mar Vista laterals, groundwater infiltration through cracks is common during winter rains. See EPA’s page on sanitary sewer overflows.
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.
If your drains slow down or back up after it rains, water is probably getting into your sewer line where it shouldn't.
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