Why does my sewer back up when I do laundry?

Author: Viola Spencer  |  Last update: Thursday, January 22, 2026

The most common cause for basement drains backing up when washing clothes is a blockage, specifically being a clogged drainpipe. Sometimes, the blockage may be caused by having a tiny drainpipe requiring you to replace it quickly.

Why does my sewer back up when I use the washing machine?

  • Lint and Debris: Over time, lint from clothing, dirt, and small items can accumulate in the drain pipe, leading to a blockage.
  • Soap Residue: Excess detergent or fabric softener can build up in the pipes, creating a thick sludge that narrows the passage and eventually causes a clog.

Why does my septic back up when I do laundry?

Doing Large Quantities of Laundry:

This can affect the natural flow and settling of solids, leading to blockages, backups, and contamination of the surrounding soils and water bodies. It's best to spread your laundry washing throughout the week so as to not overwhelm your septic system.

Why does my floor drain back up when I do laundry?

It's the result of a slow build-up of crud. As the crud builds up in the drain pipe, waste water flows slower. If a lot of water is trying to get through the drain pipe, such as when someone is taking a shower or when the washing machine is draining, you'll likely see it back up around the floor drain.

Why does my house smell like sewer when I do laundry?

Vent Pipe Clogs

As with your bathroom plumbing, washing machines need vent pipes. All drain systems in your house must be properly vented to prevent sewage gasses from seeping into your home. A clogged vent pipe can prevent sewer-smelling air from leaving your home.

How To Fix Toilets Gurgling When Washer Drains (Pipes Blockage - What Are The Solutions To Fix It?)

Why does my house smell like rotten eggs when I do laundry?

Does Your Washing Machine And Laundry Room Stink Like Rotten Eggs? If the odor comes from the washing machine, one of two things might be the cause. The most likely scenario is bacteria forming in your washing machine resulting from accumulated soap, mildew, lint, mold, and built-up dirt.

How do I get my house to stop smelling like sewer?

Clear away debris, leaves, or bird nests that might be blocking the vent. Ensure the vent stack is working correctly to allow sewer gases to escape. Inspect and Replace Wax Ring: If you suspect that the sewer smell is coming form around your toilet, you may need to inspect and repalce the wax ring seal.

How to unclog floor drain in laundry room?

Instead, use the alternatives below for the best ways to clear a clogged floor drain.
  1. Plunger. A plunger is a tool that nearly every homeowner has on hand (and if you don't have one, you should!). ...
  2. Vinegar and Soda. For this multi-step process, you'll need: ...
  3. Plumber's Snake (Manual) ...
  4. Professional Plumbers and High Tech Tools.

Why is my sink backing up when I run the washing machine?

This type of plumbing backup can get messy and usually means there's a clog further down your drainpipe or there is an issue with the drain box. This type of issue often happens beyond the sink and makes it so water can't properly escape or drain.

How to unclog main sewer line?

Your step-by-step guide: How to clear a main sewer line clog
  1. Step 1: Loosen the cap on the drain pipe. ...
  2. Step 2: Open the cap and let the buildup drain out. ...
  3. Step 3: Feed the auger cable into the drain pipe. ...
  4. Step 4: Run the auger until the clog is clear—and beyond. ...
  5. Step 5: Hose down the pipe and auger cable.

How many loads of laundry should you do a day with a septic tank?

If you need to do several loads of laundry per week, do one or two loads per day, not ten loads on any given day. 4. Reduce the use of the garbage disposal. In general, garbage disposals are a bad idea when you have a septic system as they can cause you to quickly fill your septic tank.

What are signs of septic problems?

Signs of Septic System Failure
  • Water and sewage from toilets, drains, and sinks are backing up into the home.
  • Bathtubs, showers, and sinks drain very slowly.
  • Gurgling sounds in the plumbing system.
  • Standing water or damp spots near the septic tank or drainfield.
  • Bad odors around the septic tank or drainfield.

How do I stop my septic system from backing up?

Your septic system can only handle so much water at one time and when more people are flushing the toilet, using the shower, washing their hands etc. it adds up. Avoid any extra water usage like washing the car, watering the grass and doing your laundry until after your guests have gone home.

How do I stop my sewer from backing up?

Correct illegal plumbing connections.

Consult a plumber to correct any pre-existing illegal connections. Install a backwater prevention valve, which is a fixture installed into a sewer line (and sometimes into a drain line) in the basement of your home or business to prevent sewer backflows.

Why is my poop backing up into the shower?

In our experience, clogged drains are often the culprit behind frustrating plumbing issues. In fact, we've identified some of the most common causes of clogged drains that can lead to problems like toilet backups. If you're experiencing a toilet backing up into your shower, it's likely due to a clog in the drain line.

Does a washing machine drain into a sewer line?

In most households, washing machines and sinks are designed to drain separately. The typical setup involves individual drain pipes leading to the main sewer line, ensuring each fixture has an independent pathway for wastewater.

Why does my kitchen sink back up when I run the dishwasher?

Drain Clogs

As the dishwasher pumps out water, the clog can cause a backup, resulting in water filling the sink. Solution: Start by using a plunger to attempt to dislodge the clog. If that doesn't work, try a drain snake or a mixture of baking soda and vinegar to break down the blockage.

Where is the main drain in a house?

Main drains are located in the walls and floors of your home, while sewer line drains are located outside underground. Each drain pipe in your home is connected to a different household fixture on one end, including toilets, sinks and bathtubs, and the other end is connected to the main sewer line.

Why is my drain backing up when I do laundry?

If water is backing up after a couple of loads, it probably means the backup is past the toilet and may be a clog in the main line. Your lines need cleared from a main line cleanout, which is a professional job for plumbing companies.

Why is water coming up from the floor drain when I do laundry?

If the issue is with water coming up through the basement floor drain, the issue is not with a clog in the basement floor drain itself. Instead, it's most likely an issue with your home's main drain line that is causing the floor drain to back up. Like many of us, liquids like to take the path of least resistance.

Does pouring vinegar down the drain unclog it?

Baking soda, vinegar and boiling water can help clean drains naturally, but you may need something stronger, like Liquid-Plumr ®, to fully unclog those really tough drain clogs.

How to fix sewer smell in laundry room?

If your washer hasn't been used or the water isn't draining properly, your trap may dry out. Dry traps can cause a putrid, sulfur-like smell that comes through the pipe and into your laundry room. To remedy this situation, you can add water to the drain and the smell will typically go away.

Why does my drain smell like sewage but no blockage?

Mould Formation – Mould or mildew forms inside the pipes when there is a leak and water remains standing for a while. The mould can generate a stinking odour that you can smell even from behind a wall. Plumbing Issues – Sewer smell can also be caused due to incorrect plumbing fixtures.

How to tell where sewer smell is coming from?

Where is the odor coming from? Check your home's drains, toilets, and plumbing fixtures for any signs of leaks or damage. Look for cracks, loose connections, or broken seals allowing sewer gas to escape. Additionally, inspect your sewer vents on the roof or outside your home for any obstruction or damage.

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