Why Do My Drains Back Up When It Rains in Lake Charles?

Quick Answer: When your drains back up when it rains, rainwater is entering your sewer line through cracks, joint separations, or improper connections. Your home’s drain system and the storm water system are supposed to be completely separate. When they’re not, heavy rain overloads the sewer line and pushes wastewater back into your home through the lowest fixtures. The fix requires identifying and sealing the point where rainwater is entering.

If your drains back up when it rains, you already know the pattern. A heavy storm rolls through Lake Charles, and within 30 minutes your floor drains are gurgling, the shower drain is bubbling, or wastewater is backing up through the ground-floor toilet. The rain stops, the backup drains, and everything seems fine until the next storm.

This isn’t a coincidence, and it isn’t something you should accept as normal. Drains that back up when it rains indicate a specific, diagnosable problem in your sewer system. And in Southwest Louisiana, where 55 to 60 inches of rainfall is standard in any given year, that problem will repeat over and over until the root cause is fixed.

Sewer Line Cracks and Joint Separations: The #1 Reason Drains Back Up When It Rains

This is the number one cause of rain-related backups in Calcasieu Parish homes. Your sewer line runs underground from your house to the municipal main (or septic tank). When the soil around that pipe becomes saturated during heavy rain, groundwater pressure forces water into the sewer line through any opening it can find: cracks in the pipe wall, separations at joints, corroded fittings, or gaps where root intrusion has compromised the pipe.

This is called infiltration, and it’s extremely common in older sewer lines. Cast iron pipes over 40 years old develop corrosion-related cracks. Clay pipes develop joint separations as the clay soil shifts with moisture changes. Even PVC lines can develop issues at joints if they weren’t properly glued during installation or if ground movement has stressed the connections.

The infiltrating rainwater adds volume to your sewer line that it wasn’t designed to handle. The pipe can carry your normal household wastewater without issue, but add several gallons per minute of infiltrating groundwater during a storm and the line exceeds capacity. Water backs up to the lowest available exit point in your home, which is typically a floor drain, ground-floor shower, or first-floor toilet.

A sewer camera inspection identifies the exact location and nature of the cracks or separations allowing infiltration. In many cases, trenchless pipe lining can seal the pipe from the inside without excavation, eliminating infiltration points and restoring the line to full capacity.

An Illegal or Improper Storm Water Connection

In some Lake Charles homes, particularly those built or modified before modern code enforcement, a downspout, area drain, or sump pump discharge is connected directly to the sanitary sewer line. During dry weather, this causes no noticeable problem. During a storm, it funnels roof runoff or yard drainage directly into your sewer line, overwhelming it instantly.

These connections are a code violation, and they create exactly the backup problem you’re experiencing. A plumber can trace your connections and identify whether any storm water sources are tied into the sanitary sewer. The fix involves disconnecting the improper connection and redirecting storm water to an appropriate outlet, such as a yard drain, French drain, or sump pump discharge to the surface.

The Municipal Sewer Main Is Over Capacity

During intense rainfall events, the municipal sewer main itself can reach capacity. When this happens, the system can’t accept flow from residential laterals, and water backs up through residential connections. This is a system-wide problem rather than an issue with your individual plumbing.

If your drains only back up during extremely heavy rainfall events, and you’ve confirmed your sewer line is in good condition with no infiltration, the municipal system may be the bottleneck. Contact the City of Lake Charles public works department to report the issue. While you can’t fix the municipal system yourself, you can protect your home by installing a backflow prevention device on your sewer connection. A properly installed backflow preventer allows wastewater to flow out of your home normally but closes automatically if water tries to flow back in, preventing the backup from reaching your fixtures.

Our post on spring rain season and backflow prevention covers this in more detail.

Tree Roots Are Making It Worse

Root intrusion doesn’t just block your sewer line. It also creates openings where groundwater enters. Roots that have grown into the pipe through joint separations keep those joints propped open, and during rain events, water floods through those root-enlarged gaps. The roots themselves also trap debris during normal use, reducing the pipe’s effective capacity and making it easier for the rain-related infiltration to push the line past its limit.

If your sewer line has a root intrusion problem, resolving it addresses both the root blockage and the infiltration pathway. Hydro jetting clears the roots, and pipe lining seals the joints they entered through, solving both problems in one process.

A Permanent Fix So Your Drains Never Back Up When It Rains Again

Rain-related backups aren’t something you manage. They’re something you fix. The diagnostic path is straightforward: camera inspection to identify infiltration points, repair or lining to seal them, backflow prevention to protect against municipal overflows, and correction of any improper storm water connections.

Once the infiltration is eliminated and backflow protection is in place, your drains will function normally during every rain event regardless of intensity. That includes hurricane-season storms, which produce the kind of sustained rainfall that makes unresolved infiltration problems exponentially worse.

Stop Dealing With It Every Time It Rains

If storm-related backups have become a regular event at your Lake Charles home, Advantage Plumbing can diagnose the cause and implement a permanent solution. We provide sewer camera inspections, trenchless pipe lining, hydro jetting, backflow prevention installation, and line locating for residential and commercial properties across Calcasieu Parish and Beauregard Parish.

Call (337) 496-6701 to schedule an inspection.

The EPA’s sanitary sewer overflow prevention program provides additional context on how sewer infiltration affects both residential properties and public infrastructure.

Frequently Asked Questions

Are rain-related sewer backups covered by homeowners insurance? Standard homeowners policies typically do not cover sewer backups. However, many insurers offer a sewer and drain backup endorsement as an add-on to your policy. If you live in an area prone to heavy rainfall, this endorsement is worth the additional premium. Check with your insurance provider for specific coverage details.

How do I know if the problem is my sewer line or the city’s? A sewer camera inspection of your lateral (the line from your house to the city main) will show whether your pipe has cracks, root intrusion, or other infiltration points. If your line is in good condition and backups still occur during extreme storms, the municipal system is likely the factor. A backflow preventer protects you either way.

Can I just use a sump pump to handle the backup water? A sump pump in the crawl space handles groundwater infiltration around the foundation, but it doesn’t address sewer backups coming through your drain pipes. These are two separate systems. If you have both problems, you may need both a sump pump and a backflow preventer, each addressing its respective source.

Will the backups get worse over time if my drains back up when it rains? Yes. Cracks and joint separations that allow infiltration also allow soil to enter the pipe, gradually worsening the blockage. Root intrusion grows more aggressive each year. And pipe deterioration from ongoing corrosion and soil movement means the infiltration points will only widen. Addressing the problem now prevents a progressively worsening cycle.