What Causes Sewer Backups

Sewer backups can be a messy and unpleasant problem for any homeowner. When sewage backs up into your home, it can cause unsanitary conditions, structural damage, and an overwhelming stench. Understanding what causes these backups can help you prevent them or address them quickly when they occur. In this blog post, we’ll walk through the most common causes of sewer backups so you can identify issues before they become bigger problems.

Tree Roots

One of the top causes of sewer backups is intruding tree roots. Roots from shrubs or trees planted too close to sewer lines can grow through cracks and joints in the pipes. Over time, these roots form a dense mass that collects debris and essentially creates a clog in the line. Sewage can’t pass by the clog, causing it to back up through other drains and fixtures in your home. If you suspect root growth is an issue, a plumber can inspect the lines with a sewer camera to identify any intruding roots. Severe root problems may require replacing part of the sewer line.

Pipe Failures

Sewer pipes can fail for a variety of reasons after prolonged use. Pipe materials like clay and concrete degrade over time. The seals between pipe joints can also crack and separate. When pipes are compromised, it allows debris, roots, and soil to infiltrate the sewer line and cause a clog or collapse the pipe entirely. Signs of pipe failure include visible cracks in above-ground pipes, persistent clogs, gurgling sounds, bad odors, and pooling water. A plumber can diagnose pipe issues and suggest replacement if needed.

Foreign Objects

Sometimes we unintentionally flush items down the toilet or drain that don’t belong there. Food waste, grease, paper towels, toys, and feminine hygiene products are common culprits. These foreign objects easily get snagged in pipes. As more debris accumulates behind them, it impedes the flow of wastewater and causes a backup. A strainer attached to drains can catch some of these objects before they enter pipes. However, a drain snake is usually required to fish out the blockage. Remind household members to only flush toilet paper and human waste.

Improper Drainage Slope

Sewer pipes are strategically installed with a slope to allow wastewater to flow in one direction using gravity. However, the ground can naturally settle and shift over time. This disrupts the designed slope of pipes. When wastewater can’t flow downhill, it can back up. A plumbing camera inspection can check for proper slope. In some cases, pipes may need realigning. Partial replacement or trenchless pipe lining are other options for restoring the proper slope.

Undersized Pipes

If the sewer pipes in your home are too narrow to handle the volume of wastewater, it can also lead to backups. This is most common with older homes that predate modern plumbing codes. The drain, waste, and vent pipes throughout the home should be at least 2 inches wide. However, shower, sink, toilet, and other fixture drains often connect to 1 1/2-inch branch lines. These smaller pipes can easily overload. Replacing undersized pipes with wider ones can prevent backups.

Main Sewer Line Clogs

The main sewer line carries wastewater from your home to the municipal sewer system or septic tank. These larger buried pipes are prone to the same clogging issues from roots, debris, and pipe failure. But main line clogs also frequently stem from collapsed, misaligned, or broken pipes. Significant root intrusion into the main line can also occur, especially with aging pipes. Main line clogs are challenging to locate and fix since the pipes sit underground outside your home. Professional drain cleaning, repair, and video sewer inspections are usually needed.

Backflow Prevention Failures

Many homes have backflow prevention devices installed on sewer lines. These devices only allow wastewater to flow in one direction, blocking it from backing up into the home. However, malfunctioning backflow prevention valves can fail to close properly and permit backups. A broken device may produce gurgling sounds when fixtures drain. A plumber can diagnose and replace defective backflow preventers. Proper installation is also key to prevent reverse wastewater flow.

Fixture and Floor Drain Leaks

Leaking fixtures like sinks, tubs, and toilets can contribute to sewer backups in some cases. The small leaks add extra water volume to drain lines over time. If this accumulation of water overwhelms the pipes, it could regurgitate through other drains as a backup. Leaking roof drains and basement floor drains connected to the sewer can also inundate the system with excess stormwater. Identifying and fixing all fixture and drain leaks removes this unnecessary burden on your sewer line.

Fat, Oil and Grease Buildup

Fat, oil and grease washed down kitchen sinks are a common source of sewer clogs. These thick substances congeal and coat the inside of drain pipes. Food particles and other debris stick to this layer of grease and fat, creating a hard mass that blocks wastewater flow. Eventually, the added pressure can cause backups. Avoid pouring fats and oils down sinks. Use strainers in drains to catch food scraps. Over time, a plumber may need to hydrojet pipes to scour away grease deposits.

Septic System Failures

Homes on a septic system depend on the septic tank and drain field to treat wastewater. But when these components malfunction, sewage can back up into the home. Signs of septic problems include foul odors, soggy ground, and slow drains. The most common causes are full septic tanks, clogged drain field pipes, and drain field overloading. An inspection and pumping from a septic professional can identify and resolve many issues. However, drain field repairs or replacement may ultimately be necessary.

Sewer Line Blockages Downstream

Sometimes a clog or blockage occurs downstream in the main municipal sewer lines. This can create backups that reverberate through connected homes’ plumbing. Heavy rainfall can also overwhelm the public sewer system and cause overflows. Since the issue originates off your property, there is little you can do to fix it. However, the local wastewater authority or your neighbors will likely notice the problem too. You may simply need to wait for crews to clear the downstream blockage before your backup dissipates.

Damaged or Clogged Vent Pipes

Sewer gases need proper venting to flow out of drain pipes. Vent pipes extend from drains through the roof, providing an escape route. But when vents become obstructed by debris or broken by falling trees or debris, gases can’t exhaust. This can siphon water out of drain traps, allowing sewer gases to enter the home. It also creates pressure imbalances in the plumbing that lead to backups. Inspecting vent pipes for damage and clearing any obstructions can restore proper drain venting.

Improperly Installed Plumbing

Incorrect installation of cleanouts, backflow prevention valves and other plumbing components can disrupt wastewater flow in drains. Cleanouts need to be oriented in the direction of the flow. Backflow valves must also be positioned according to manufacturer specifications. If a plumber neglects these guidelines while installing new plumbing, it can render devices ineffective and cause sewage to back up unexpectedly. The problem may only become apparent over time. Reversal or replacement of improperly installed plumbing is needed to stop backups.

Combination of Causes

In many homes, sewer backups occur due to a combination of factors, not just one isolated issue. For example, roots infiltrating through cracked pipes weakened by age. Or undersized pipes made worse by added grease and foreign objects. Evaluating your particular symptoms and inspection results will help determine if a multifaceted issue is at play. Comprehensive plumbing repairs may be required to fix all components contributing to backups. Don’t assume there is a single cause.

By understanding the various causes of sewer backups, you can help minimize risks in your home’s plumbing system. Perform regular drain inspections and maintenance. Don’t ignore gurgling sounds or slow drains – have a professional diagnose potential problems promptly. If backups do occur, identify the source right away so it can be addressed before resulting in costly damage. With proper preventative care and quick response, you can keep wastewater flowing properly and prevent unpleasant sewer backups.

Dealing with sewer backups around North and Central Georgia? Contact Southeast Water Restoration immediately for water damage restoration!