Does Washing Machine Drain Into Sewer Line? [Quick Answer!]

As a washing machine user, you would love your washer’s waste to end at the main sewer line. But is that really the case? Does washing machine drain into sewer line?

Most washing machines drain into the sewer line upon installing a standpipe. The standpipe funnels the wastewater from the washer’s drain hose into the sewer line. But other than the standpipe, you can also opt for the laundry tub or underground pipe-link drainage options.

Note, however, that other than discharging the wastewater into the sewer line, you could opt to do it into the septic tank if connected or the yard if it’s graywater.

Basically, there are several drainage options to consider, and we will discuss them all. Nonetheless, our focus will be on the sewer line, how it works, and how you can connect and drain the washer into it.

Without further ado, let’s jump into it.

Where should a washing machine drain to

Sewer Line as an Option – Does Washing Machine Drain into Sewer Line?

Like every household water fixture and appliance, the washing machine utilizes your domestic water supply to clean the laundry.

After cleaning, it ejects its wastewater through a drain pipe which you can connect to any drainage system, including the sewer line.

So, yes, a washing machine can drain into the sewer line. I’m using the word ‘can’ to show possibility but not a compulsory thing.

You can opt for the septic tank if it’s within access or the yard. Note, however, that draining to the sewer line is the safest and most convenient way.

You’ll, however, have to do a bit of heavy lifting (or hire someone to do it) to connect the two.

Let’s jump to the process:

4 Steps for Connecting the Washing Machine to The Sewer Line

It’s generally essential to correctly connect the washer to the sewer line to avoid overflows during draining. For that to be the case, these four steps are a must follow:

Step 1 (Drain Hose Locating)

Start by locating your washer’s drain hose. It’s a plastic tube on the machine’s rear end that juts from the pump.

Step 2 (Determine The Drain Hoses Size)

It’s important that the drain hose reaches the sewers standpipe without any kinks, bends, or obstructions to prevent backups in the future. If the hose is longer than it should, cut it to size using a razor knife.

how does washing machine drain work

Step 3 (Drain Hose and Standpipe Interconnection)

Now take the open end of your washer’s drain tube and the open end of the sewers standpipe and join the two.

The drain hose should go into the standpipe at a considerable depth until it feels secure. Thus, your washer drain hose should be narrower than the sewer’s standpipe.

Step 4 (Joint Securing)

Lastly, use cable ties or any other fastener to secure the two pipes (drain hose and standpipe). While it’s essential to secure the two tight, you should pull the cable tie so tightly for creases to form. That will ensure the drain hose holds and does not result in flooding.


You’ll need these supplies for the above process: a razor knife, cable ties, and standpipe (which should be installed in your sewer system). If your drain hose is short, get a long drain hose and cut it to size.

How Does Washing Machine Drain Work?

Now that you know that it’s possible to drain your washing machine into the sewer line and how you can connect the two, let’s talk about how the drain works.

Your washing machine has two critical components essential in the discharge of wastewater.

First, we have the drain hose, which is the passage that the wastewater passes through. Second, we have the pump whose job is to force the water from the tub into the drain hose and, lastly, to the standpipe.

So, if these components work as expected, water moves smoothly from the tub into the hose and, lastly, gets into the standpipe. From the standpipe, the wastewater joins the main sewer line.

3 Commonest Washing Machine Drainage Options

Picking the right drainage option for your washing machine is crucial as it dictates how convenient the wastewater will discharge.

Overall, here are the commonest drainage options for washing machines for your consideration:

1. Standpipe Drainage – Cheapest Drainage Option

Having already mentioned the standpipe, it’s worth noting that the reason for that is because it’s the cheapest and often the most space-saving.

As a result, most homeowners settle for it, making it the most popular drainage solution at home. All it takes is the installation of a standpipe and connecting it to your washer’s drain hose using the steps I shared earlier.

However, ensure you pick a standpipe with a 2-inch diameter to ensure smooth wastewater flow.

Overall, instead of attaching your washer directly to the sewer line, a standpipe allows you to have the perfect connection between the two, preventing backup and unpleasant fumes. 

Furthermore, you don’t have to be an expert plumber to install a standpipe, but you need basic piping knowledge.

2. Laundry Tub Drainage (Clothing Tub) – Most Efficient Drainage Option

If you want to replace your dirty laundry water with clean water, you need a quick way to discharge wastewater, and a laundry tub promises that.

This method is quite efficient in draining waste and sits 25-30 inches above your floor surface, while the laundry tub sits 12-18 inches beneath the washing machine.

That allows a smooth flow of wastewater from the washer to the laundry tub through the drain hose. Overall, you don’t have to be an expert plumber to install a laundry tub.

washing machine drainage options

3. Underground Pipe-Link – Best Permanent Option

If you are not planning to change the location of your laundry room any time soon, installing an underground pipe-link is advisable. It’s more reliable than the other two, though it requires far-reaching plumbing knowledge and costs slightly more.

The connection is usually fitted behind the wall, so you have to bring a part of the wall down to fix it. However, the good news is that the system doesn’t develop issues quickly. So, you may not need to tear down your wall.

The Outside Option – Can Washing Machine Water Drain into Yard?

If you have a yard, it’s tempting to discharge the washing machine’s wastewater into it. The question, however, is can you do it? Or should you do it?

Well, it’s only recommendable to discharge graywater into the yard. That brings us to the next question,’ what’s graywater?’

Graywater is detergent discharge water free from toxic chemicals and pathogenic microorganisms. It’s water that doesn’t cause damage to your yard or plants, and if it does, the damage is only minimal.

So, this is very different from the toilet’s black water. It’s also vital that you consider the kind of plants in your yard. If they are edible such as vegetables, fruit plants, vines, or just flowers, it’s not advisable to discharge graywater into the yard.

Last but not least, consider the yard’s gradient. It’s crucial that you contain the graywater discharge within your yard. It shouldn’t be washed downslope to other people’s lands. So, if you have a sloped yard, avoid discharging graywater into it. 

What Not to Drain to The Yard When Draining Your Washing Machine

It’s important not to discharge any laundry water that could damage your plants or yard when draining your washing machine. That means the water shouldn’t have any of these:

  • Feces – Don’t discharge the water to the yard after washing diaper clothes. That’ll no longer be graywater but Blackwater.
  • Bleach – Bleach has herbicidal properties. It can quickly kill your plants and beneficial microbes in the soil. Consequently, don’t discharge water with bleach into the yard.
  • Sodium Detergents – Not all detergents are harmful, but you should avoid sodium-based. Sodium is toxic to plants. It can kill the plant’s cells or result in stunted growth.
Can washing machine water drain into yard

Why Does My Sewer Back Up When I Use the Washing Machine?

One of the most dreading challenges of connecting your washing machine to the sewer line is sewer backup, where wastewater fails to drain correctly due to damage, incorrect fitting, or obstruction.

Generally, here are the reasons why you may suffer a sewer backup after fitting your washing machine to the sewer line:

  • Wastewater is not draining entirely out of your washing machine
  • Though water may be draining out of your washing machine, there could be a blockage within the pipe
  • There’s a clog in your p-trap
  • Your washing machine and kitchen sinks share the same drain
  • Your pipes are cast iron

Once you know the problem, you should fix it or hire an expert plumber to help you.

People Also Ask

1. Where Should a Washing Machine Drain to?

The washing machine should drain into the sewer line. You can ensure that by picking the right drainage option between the washer drain and the sewer system. But still, you can drain it into the septic tank or yard if it’s graywater.  

2. Should Washer Drain into Septic Tank?

The washer can drain into the septic tank if you connect the two properly to prevent overflow. You need to join the washer’s drain hose to the septic line to allow a smooth flow of wastewater from the washer to the septic tank.

3. Why Does My Washing Machine Drain into The Sink?

Your washing machine is draining into the sink because of a venting problem or clogging in its drain. In the first case, you should vent out the washer’s drainpipe to properly redirect the wastewater into the sewer system. However, in the second case, unblock the drain to improve wastewater flow into the sewer.

4. How Do I Know If My Washing Machine Drain Is Clogged?

You can know if your washing machine drain is clogged if there’s an overflow, sewer backup, or water flooding upon discharge. If clogged, consider using a plumber’s anger or drain snake to unclog it.

5. Can I Use Bleach in My Washing Machine If I Have a Septic Tank?

Too much bleach can damage septic tanks. So, you shouldn’t discharge washing machine wastewater into the septic tank if you use excess bleach. Do it if you use bleach in moderation.

6. Can You Connect Washing Machine To Toilet?

The washing machine and toilet drains can connect to the main sewer line. So, while the two shouldn’t share the same drain, they eventually join with other drains at the main sewer line.

Does Washing Machine Drain into Sewer Line? Closing Remarks!

As shared, the washing machine can drain into the sewer line if you connect the washer’s drain hose with the sewer’s standpipe.

Note that your washing machine can still drain to the septic tank or the yard (if it’s graywater).

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