Why Your Drains Back Up During Heavy Rains

Are you asking yourself, “Why do my drains back up when it rains?” Many homeowners in the heart of Missouri find themselves dealing with hazardous and damaging backups during or after heavy storms. Drains gurgling, floor drains overflowing, or water coming up from the toilet are signs that your home’s plumbing and drainage systems are struggling to keep up.

Superior Sewer Solutions is the leading Jefferson City, Missouri, sewer system expert team. We’ve seen firsthand how the combination of aging infrastructure, unpredictable weather, and overlooked maintenance can create the perfect storm for drain backups. Let’s break down what’s happening, why it matters, and how to prevent it.

Heavy Rainfall and Your Drainage System: A Dangerous Mix

When storms roll into Missouri, the volume of water your home must manage surges. Unfortunately, residential drainage systems generally aren’t designed to handle extreme, sudden inflows of rainwater on top of daily household waste. That heavy rainfall impact often overwhelms both your private sewer lines and the municipal stormwater network.

In older developments or low-lying neighborhoods, combined sewer systems, which carry both rainwater and sewage, are still prevalent. During a major storm, excess runoff from roofs, driveways, and streets floods these pipes. Once water exceeds capacity, the resulting storm drain overflows send pressure backward through the system. That pressure is often the leading answer to, “Why do my drains back up when it rains?”

Sewer Line Backups: When Waste Has Nowhere To Go

Sewer line backups happen when wastewater can’t exit to the main sewer fast enough. With nowhere to go, the sewage backs up into your lowest drains, typically your basement floor drains or the lowest-level toilets.

Heavy storms make this more likely due to the excess load on the system. Aging or compromised pipes on your property can make the problem worse, as tree roots, cracks, or built-up grease and sediment restrict flow. When a storm hits, obstructions act as a plug, turning an already overloaded system into a direct threat to your home.

Groundwater Saturation: The Hidden Pressure Point

As heavy rain continues, the soil around your foundation and across your yard becomes waterlogged. Groundwater saturation turns your property into a soaked sponge that can’t absorb more moisture. The force of this water buildup, called hydrostatic pressure, pushes waves of above- and below-ground water toward your home’s foundation and into any available opening.

Sump pumps redirect this excess water, but an outdated or poorly maintained system won’t keep up. In some instances, groundwater pressure can cause damage to underground pipes. Of course, that only compounds the risk of backups.

Blocked Pipes and Poor Yard Drainage: Localized but Serious

“Why do my drains back up when it rains?” Even if your neighborhood’s stormwater infrastructure is fine, problems on your property may still lead to backups in your home. Blocked drain pipes from grease, soap scum, hair, or tree roots reduce flow capacity. Under normal conditions, they may not cause noticeable issues. However, heavy rainfall can quickly tip the balance and lead to backups.  

Poor drainage systems on residential lots often make this problem much worse. We often encounter on-site drainage problems during emergency calls, including:

• Improper grading that directs water toward a foundation rather than away
• Short downspouts that dump water directly along foundations
• Clogged gutters that cause overflows down walls and onto foundations

Heavy runoff that isn’t controlled can quickly find its way into your plumbing system when storm levels rise.

How To Prevent the Next Backup

Experienced service providers believe the best defense is proactive care. Here’s how to prepare:

• Get a camera inspection of your sewer lines and plumbing to check for cracks, clogs, or intrusions.
• Schedule professional hydro jetting to remove grease, debris, and roots from your plumbing.
• Install a backwater valve to prevent municipal sewage from backing into your home.
• Redirect rainwater by cleaning gutters, extending downspouts, and grading soil away from your foundation.

Stay ahead of the storm and protect your home before the next downpour strikes.

Let Superior Sewer Solutions Keep Your Drains Flowing, Rain or Shine

Now that we’ve explored “Why do my drains back up when it rains?” we invite you to contact our expert team in Jefferson City for professional drain cleaning services. Whether you’re dealing with a storm drain overflow, blocked drain pipes, or a poorly functioning drainage system, we have solutions for all drainage issues.

If you have dealt with recurring backups or want to prevent them before the next big downpour, call us today at (573) 301-0141. We’ll inspect your system, recommend improvements, and make sure your drains are ready for whatever the weather brings.