5 Surprising Causes of Sewer Backups in Summer (and How to Prevent Them)

When most people think about sewer issues, they often associate them with cold-weather problems like frozen pipes or cracked lines from freezing temperatures. However, summer brings its unique plumbing risks, particularly in areas like Bethel Park, Mt. Lebanon, South Fayette, and the surrounding South Hills neighborhoods, where many homes have aging infrastructure.

Increased rainfall, outdoor activities, and rising temperatures can all contribute to problems with your sewer system—sometimes in unexpected ways. 

1. Tree Root Intrusion

Summer is growing season for not only your garden, but also tree roots. During dry periods, roots naturally stretch out in search of moisture. Sewer lines, particularly older ones made from clay, cast iron, or other porous materials, are especially vulnerable. Tiny cracks or loose joints can allow roots to enter and begin growing inside the pipe.

Once inside, the roots continue to expand, gradually blocking water flow. In some cases, they can even cause structural damage to the pipe, causing a partial or full collapse.

Signs to Watch For

• Gurgling or bubbling noises in toilets

• Multiple slow-draining fixtures (like sinks and showers)

• Sewage odors in the basement

• Water backing up in basement drains or toilets

How to Prevent It

Routine sewer camera inspections are one of the most accurate ways to detect root intrusion before it causes a blockage. At All Pro Plumbing, we use high-resolution camera technology to identify root entry points and help you address issues early, before excavation or emergency repairs become necessary. If roots are discovered, root cutting or hydro jetting may be recommended to clear them out safely.

2. Heavy Rainfall and Storm Runoff

The South Hills region sees frequent heavy downpours in summer. Many neighborhoods have older or combined sewer systems, where both stormwater and wastewater flow through the same pipes. During a period of heavy rain, these systems can become overwhelmed, and excess pressure can push water backward into your home's drains.

This problem is especially pronounced in basements, where floor drains and lower-level plumbing fixtures are more vulnerable to reverse flow.

Prevention Tools to Consider

Backwater Valve: This mechanical valve is installed on your main sewer line to prevent sewage from backing up into your home. When the system is working normally, the valve remains open. But if it senses reverse flow, it shuts automatically to block the backup.

Sump Pump with Battery Backup: This device removes excess groundwater from your basement. Adding a battery backup ensures it continues running even during a power outage—something that often accompanies summer storms.

Taking these steps can help protect your property during even the most intense downpours.

3. Landscaping and Outdoor Projects Gone Wrong

Summer is the prime time for home improvements. Whether you're installing a new fence, planting trees, or creating a patio space, many of these projects involve digging. Unfortunately, digging without accurate knowledge of your underground utility layout can accidentally damage or place pressure on your sewer lines.

Even minor shifts in soil from heavy machinery or newly compacted ground can lead to misaligned or crushed pipes—especially if your sewer line is already aging or weakened.

Safe Practices

Call 811 Before You Dig: This free service will mark all underground utilities, including water, gas, and sewer lines, so you can avoid them.

Work With a Plumber for Larger Projects: If your landscaping plans involve excavation or large equipment, it's worth having a licensed plumber evaluate your property beforehand. At All Pro Plumbing, we help homeowners identify safe zones for digging and advise on how to protect buried infrastructure.

Being proactive before you start your project is much easier than dealing with a broken sewer line later.

4. Clogged Outdoor Drains and Gutters

Outdoor drainage systems are your home's first line of defense against water intrusion. But in summer, these systems can become clogged with lawn clippings, mulch, flower petals, and leaves from nearby trees. When storm drains or gutters are blocked, rainwater often spills over, saturating the soil around your home.

This extra water can exert pressure on your foundation and sewer pipes, making it easier for water to seep in or trigger backups—especially if your home is in a low-lying area.

Warning Signs

• Puddles or soggy ground near the foundation

• Overflowing gutters during rainstorms

• Water draining slowly from exterior drains or catch basins

Simple Preventive Measures

• Clean gutters and downspouts regularly, especially after storms or yard work.

• Install gutter guards to reduce future clogs.

• Inspect and clear outdoor storm drains in driveways or patios.

• Consider regrading or adding drainage swales if water tends to collect in one area.

Keeping exterior drainage working properly can significantly reduce stress on your sewer system.

5. Flushing the Wrong Items During Summer Gatherings

Summer often means more foot traffic through your home—barbecues, houseguests, or kids home from school all lead to increased plumbing use. With more people using the bathrooms and kitchen, there's a higher risk that someone might flush or rinse something they shouldn't.

Non-flushable items like paper towels, wet wipes, cotton swabs, and even grease from cookouts can cause clogs when they enter your system. If your pipes are already partially blocked by roots or buildup, one wrong flush could trigger a full backup.

Best Practices

• Use wastebaskets in all bathrooms for anything other than toilet paper

• Post polite reminders during parties about what not to flush

• Avoid rinsing grease or food scraps down the drain. Instead, dispose of them in the trash or compost

• Install a mesh strainer over kitchen drains to catch solids

Small habits can go a long way in maintaining a trouble-free sewer system.

What to Do if You Suspect a Sewer Problem

Sewer issues rarely appear out of nowhere. Most problems build up over time. Recognizing the early signs of plumbing trouble can help you avoid expensive cleanup and water damage. Red flags to watch out for:

• Multiple drains are slow or bubbling

• You smell sewage in the basement, yard, or from fixtures

• Wet or sunken patches appear in your yard

• Wastewater backs up during or after rainstorms

\If you notice any of these symptoms, don't ignore them. The earlier you act, the more options you have for repair. Be sure to call your South Hills plumber, All Pro Plumbing, to resolve the problem before it escalates. 

Why Homeowners in the South Hills Trust All Pro Plumbing

At All Pro Plumbing, we specialize in helping South Hills homeowners protect their plumbing systems all year round. Whether you're noticing early signs of sewer trouble or want peace of mind before starting a summer project, our licensed team offers the tools and experience needed to help.

Our Services Include:

• Sewer Camera Inspections

• Trenchless Pipe Repair (when applicable)

• Emergency Plumbing Services, 24/7

• Transparent Estimates and Upfront Pricing

• Local Knowledge of South Hills Sewer Systems

We don't push unnecessary services—we help you understand your repair or replacement options so you can make informed decisions.

Schedule a Sewer Inspection Before Problems Escalate

A preventive inspection today can spare you from an emergency tomorrow. Whether you're dealing with frequent rain, a major yard project, or simply more people using your plumbing system, summer is a great time to check in on your sewer health.

Contact All Pro Plumbing to schedule your sewer camera inspection or sewer line repair. South Hills and surrounding area homeowners in Bethel Park and Allegheny County can count on us for reliable service to keep their homes' plumbing running smoothly.