Why Do My Drains Back Up When It Rains?

In many areas of the United States, rainy periods cloud at least one season. The severity of rainfall varies based on the area, but many states receive torrential downpours every now and again. When the clouds open and release inches of rain on a single location, they can cause a string of negative occurrences.

Key Points:

  • Rainfall can overload plumbing systems, leading to bent and cracked pipes, flooding of low points around the home, and sewage backup in drains.
  • Damage caused by excess rainwater pressure can result in discolored or coppery-tasting water, mildew smells, and other signs of plumbing distress.
  • Clogs caused by debris brought by heavy rainfall can block entire sewage systems and lead to water pooling around household drains.

Unfortunately, plumbing systems might be one of the areas affected by this excess water. When a plumbing system can’t handle all this water, you might notice sewage backup rising in the drains throughout your home. This is a severe problem that requires the attention of a licensed plumber, so if your drains back up regularly, here’s what you need to know.

Can Rain Cause Plumbing Problems?

Rain can create an abundance of plumbing problems. Although you might not think the rain seeping into the ground will affect your home’s plumbing, the possibility is there, especially if you’re unprepared.

Heavy rains can put excessive pressure on the plumbing as it soaks into the sand and dirt around the pipes, making the soil heavier. In addition, underground pipes can actually move around if it rains heavily enough. The earth around the lines softens considerably when wet, allowing the pipes to move.

Combined with increased pressure, this movement can allow your pipes to bend and crack, causing significant problems for the plumbing connecting to your home. Here are the most common issues associated with heavy rain:


When heavy rains plague your area for hours or days on end, water often begins to pool in low points and dips in your yard. If there are low points near your home’s foundation, water can start to damage the concrete, potentially causing cracks as the water slowly weakens the foundation.

Large amounts of rainwater can seep into the ground around your home, especially when there isn’t an adequate drainage system to whisk excess water away from your home. The water will seep into the earth, making the soil around the plumbing heavy, thus increasing pressure on the pipes.

Burst Or Cracked Pipes

Broken plumbing is a major issue that most homeowners experience at least once. When the plumbing in your home cracks or bursts, you’ll usually notice a few symptoms. If the crack is minor, you might notice the water from your faucet is discolored or tastes coppery.

Or, your might smell mildew but can’t isolate where it’s coming from. In more severe cases, broken pipes can cause significant water damage in your home. However, this depends on where the crack or break occurs.

When rainwater accumulates around your home without any drainage route, it puts excessive pressure on the plumbing. With enough pressure, the pipes can break, especially if they’re old or have pre-existing damage.

When these pipes break, it can affect the freshwater that enters your home, causing it to take on a strange taste or color.

Sewage Backup

Heavy rainfall can lead to a buildup of debris in the outdoor drains around your home. When this occurs, the buildup can eventually affect your main sewer line. This line carries wastewater out of your home, escorting it to the municipal sewer line. If this pipe becomes clogged with debris, sewage will not have an exit route out of your home.

This can lead to backups in drains throughout your home, eventually pooling as the dirty sewage water doesn’t have anywhere to go. In severe scenarios, the blockage can even cause your pipes to crack or burst.

Clogs And Blockages

Excessive rain can escort debris into your sewage system, such as leaves, sticks, soil, and trash. If enough waste builds up in the system, it can completely block the entire plumbing network, causing water to back up into your home. You might notice water pooling in your sinks, showers, bathtubs, or near other household drains as the water backs up due to heavy rain.

What Are The Signs Of A Sewer Backup?

Drain Backed Up

When your sewer backs up, you’ll usually know almost right away. Generally, the quicker you catch the problem, the better the outcome. Here are the most common signs of a sewer backup:

Pungent Odors

The plumbing throughout your home that takes sewage out of your home is far from clean, especially considering what it whisks away. So, when your sewage line backs up, you’ll usually notice an awful smell emanating from the drains in your home.

Generally, this happens because the wastewater in the pipes is stuck with no way out. This leads to a foul odor wafting from the drains in your home.

Slow-Draining Water

If you notice the drains and toilets throughout your home seem to be draining slowly, you might have a sewer blockage. Check a drain or toilet in the basement of your home, as this will help you determine whether the problem is isolated to a single drain or widespread throughout your home.

If the main line has a blockage, the problem will persist throughout your entire home.

Standing Water

Many homes feature floor drains in the laundry room, basement (often in the maintenance room), and attached garages. You might notice standing water pooling around these drains when your sewage line backs up. In most cases, sewer lines will back up here first before affecting the other drains in your home.

If there’s water pooling here, this is a strong indicator that wastewater cannot freely flow out and away from your home.

Gurgling Noises

Slow draining is often accompanied by gurgling noises as the water tries to drain. You might hear a bubbling or gurgling noise coming from water-using appliances like your washing machine or dishwasher, which can indicate a blockage in the main sewer line.

There shouldn’t be gurgling from toilets, drains, or water-using appliances, so you need to call a plumber for assistance, as there may be a full or partial blockage.

How Do You Stop Sewer Backup From Raining?

Sewer backups are a nuisance and can potentially create incredibly expensive problems. So, to avoid these issues, use preventative methods, like installing a proper drain system or backwater check valves.

Figure Out An Outdoor Drainage System

If your yard regularly houses pools of water when it rains, it might be a matter of time before problems begin to occur. Ideally, you could invest in a drainage system to escort the water away from your home, like a gently sloped yard, gravel to assist with drainage, and an effective gutter system to direct water away from the foundation.

Install Check Valves

Check valves are devices for drains throughout your home that allow water to run out of the drain but prevent water from coming back up the drain. It doesn’t hurt to install these valves throughout your home, especially on your floor drains and on basement plumbing fixtures (usually affected first in sewer backups).

This will help prevent flooding in your basement and other associated issues when it rains heavily, and the municipal sanitary sewer system is overwhelmed. Your plumber can install these valves for you, or you can DIY the project if you’re handy with this type of thing.

Invest In A Sump Pump

Investing in a sump pump might not hurt if you live in a wet climate that regularly receives torrential rains (or in a dry environment that seasonally experiences sudden, heavy rain). These pumps feature a mechanism that monitors elevating water levels and pumps it out as necessary.

Some homes have gray water sump pumps to escort used household water away from the house when gravity is unable to. Alternatively, other homes have groundwater sump pumps that prevent groundwater from seeping into your home and causing problems.

Investing in a sump pump can help keep the dirt around your home dry (and more stable), which helps protect underground plumbing and your home’s foundation.

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