Every now and then something strange happens that is simultaneously baffling and frustrating in your home. Gray water from your washing machine backing up into your sink is one such problem and for many homeowners, it can be an ongoing source of annoyance.

Why Is My Sink Backing Up?

If your kitchen sink is backing up when washing laundry you may have a clogged drain or a venting issue, but it could be other issues. Start to identify the problem and contact your local plumbing company for help.

To start with, know that your sink and washing machine drain lines tend to run congruent to each other. This means they combine at some point on the way to the main sewer line. So, if there is a problem after they combine, it can affect both systems.


First, you must pinpoint the problem. More often than not, a washing machine backup will occur in one or more sinks during or after the drain cycle of your washing machine. This may not happen every time or it may get progressively worse. It depends on why it is happening in the first place.

If the sink doesn’t back up on its own when you do the dishes or run the faucet, the clog is probably deeper in the pipes and only responds to the large volume of water being drained from your washing machine. In either case, you probably have a clog in the drainage pipe after the two combine.


The washing machine uses too much water for the drain

Your washing machine might use too much water due to incorrect load size settings, malfunctioning water level sensors, or a faulty inlet valve. Over time, wear and tear can impair these components, causing the machine to overfill. Regular checks and maintenance can prevent this and potential drainage issues.

House has cast-iron pipes

Houses with cast iron pipes can face problems like corrosion, rusting, and sediment buildup. Over time, these pipes may develop leaks or become brittle and break. The accumulated rust can also lead to discolored water and reduced water flow, potentially impacting water quality and overall plumbing efficiency.

The p-trap is clogged

A P-trap is a U-shaped section of a drainpipe that is designed to trap a small amount of water in it at all times. This standing water acts as a seal to prevent sewer gases from entering a building through a fixture's drain, such as a sink, bathtub, or toilet. The curvature also allows for the easy removal of obstructions and debris. If the trap dries out or becomes clogged, it can allow sewer odors to seep into the living space.

If you're experiencing any of these issues, contact our team of expert plumbers. We'll be able to diagnose your issue and give you a quote for the repairs. 


Do NOT use any chemicals to clear the clog. Not only do chemicals cause damage to your pipes, which can lead to cracks and leaks later, they are not always effective at actually removing the problem – they simply minimize it in the short term.

At YES! Air Conditioning, Heating, Plumbing, and Electric we have the equipment and knowledge to locate and clear stoppages so give us a call for an appointment and we will diagnose and clear any blockages you may have in your home.

For additional information on plumbing services, call our team at 844-216-9300 and speak with a technician today.