Washing Machine Drainage Options

There are two main drainage options for a washing machine, a sewer and a gray water septic system. Both methods have a few pros vs cons to consider. Draining a washing machine into a sewer line is the best option. But it only works if your home has access to a public sewer system. Water from your washing machine runs directly into the sewer along with wastewater from your showers, sinks, and toilets. The problem with this method is that many rural communities don’t have a municipal sewer system to tap into. And if there’s an issue with the public sewer system, which happens commonly after big storms and floods, you can’t wash your clothes until it’s fixed.

If you live in an area that does not have public sewer, the best drainage option for a washing machine is a gray water system. A gray water system works just like a septic system, except it’s only for household wastewater from sinks, showers, dishwashers and washing machines, not sewage. The wastewater is drained out of the house, through the gray water system, and safely dispersed underground.

If you need a temporary drainage hookup for a washing machine, a slop sink is a good option. Run a drain from the back of the washer into the sink until you can permanently connect the washer to your sewer drain. You can also run a temporary drain line from the washer to the area of your yard where your gray water is drained. Both of these methods can work as short term solutions until you can properly connect the washer drain.

Where Should A Washing Machine Drain To?

A washing machine should drain into a public sewer system or a gray water system. Draining a washing machine into a municipal sewer is the best option and usually adds value to your home. A gray water system is considered a secondary option to a sewer and is used when the home has a septic tank.

Where your washing machine water should drain depends on if there’s access to a public sewer or not.

If your home is connected to a public sewer system, your washing machine drains into the sewer.
If your home doesn’t have access to public sewer, it probably uses a septic system and gray water.

With a septic system, sewage drains into a septic tank which eventually needs to be pumped out. However, wastewater from washing machines, sinks, showers and dishwashers drain into a gray water system.

Unlike a septic tank, a gray water system doesn’t have to be pumped out. Instead, wastewater is safely released into the soil at a safe distance away from your home.

If your home has access to a public sewer, washing machine water drains into the sewer.
The sewer also drains wastewater from sinks, showers, and toilets.
If your home has a septic system and no sewer access, your washing machine drains into a gray water system.
Washing machines should not drain into your septic tank.
Wastewater from washing machines should be drained separate from sewage.

A sewer and gray water system are the two most common ways to drain a washing machine. Draining into a sewer is the best choice if your home has access to a public sewer. However, a septic tank and separate gray water system is a great way to drain a washing machine if the home has no sewer access.

How To Drain A Washing Machine

The water in your washing machine can be drained in a few different ways. The best way is into a public sewer along with your toilets, sinks and showers. However, not all homes have access to a municipal sewer system.

If you live in a rural area or somewhere that does not have sewer access, you probably have a septic system. In this case, a machine machine should drain into a gray water system.

A gray water system is separate from a septic tank and handles wastewater from sinks, showers, washings and dishwashers, not sewage.

Sewer Line

The best way to drain a washing machine is into a sewer line. If your home has public sewer access, a main drain pipe will run from your house into the sewer. All your small drains, like toilets, sinks, washing machines, dishwashers, tubs and showers flow into the main drain. To drain a washing machine into the sewer, you simply connect the washing machine drain to the home’s main drain pipe. In most home’s it’s located in the basement or crawl space.

Drains work because gravity always pulls water down hill. So the washing machine, and other drains, must be located above the home’s main drain pipe. . If your washing machine is located in a basement that’s lower than the main drain line, you’ll need a pump to force water up and into the drain. This is true of basement sinks, showers and toilets as well.

A sewer line is the best way to drain a washing machine.
Your washing machine drain pipe should empty into the home’s main sewer line.
The washing machine drain should be located above the main sewer line.
If the washing machine is below the home’s main sewer line, you’ll need a water pump.

Installing a new washing machine drain pipe requires a plumber. Plumbing building codes must be followed to prevent washing machine water from backing up into the washing machine or flooding your home. Your new washing machine drain will also need a P-trap installed at the correct height and your drain piping must the proper size.

Gray Water System

If your home doesn’t have access to a public sewer system, the best way to drain a washing machine is with a gray water system. Gray water is water from your bathroom sinks, showers, tubs, dishwashers and washing machines. Any water that drains from the home, other than toilets, is considered gray water.

Gray water systems function in the same basic way as a sewer system. Water from your washing machine pours into a main drain and then out of the house. The difference is that instead of the drain running into a sewer, it fills a below ground dispersal system, like a dry well.

Gray water is not water that comes into contact with feces, either from the toilet or from washing diapers.
A gray water system is a crucial part of a septic system.
“Gray Water” isn’t sewage but it’s not clean water either.
Water from washing machines, sinks, showers, dishwashers and baths are considered gray water.
Gray water isn’t drinkable, but it’s safe for irrigation use and can be released onto your property.
Gray water systems disperses water below ground and away from the home.

Like other washing machine drainage systems, a gray water system should be designed and installed by a licensed professionals. If the system isn’t designed and/or built properly, water can backup into the house, flood or cause standing water issues.

In a gray water system, a main drain pipe from the house runs into an underground dispersal system, such as a dry well. The water must be dispersed at least 12 feet (3.7 meters) away from the home to prevent draining into the foundation.

Gray water inside the dry well, or dispersal system, will safely percolate into the surrounding soil without causing erosion, sinkholes, flooding or backups into the home.

Can You Drain A Washing Machine Into A Utility Sink?

A utility sink isn’t the best place to drain a washing machine, but it’ll work temporarily. In fact, any sink will work as a temporary washing machine drain as long as the drain pipe is big enough to handle the water from the washer.

A typical sink has a drain pipe 1.5 inches in diameter, but a washing machine has a 2 inch diameter drain. If you drain a washing machine into a sink with a 1.5 inch diameter drain, it will overflow and flood the laundry.

Draining a washing machine directly into a sewer line or a gray water system are the best solutions. However, a utility sink can be used as a backup or a temporary solution if you need one.

You can drain your washing machine into a sink as a temporary or emergency solution.
Run the washing machine drain hose over the edge of the sink and into the sink drain.
Make sure the drain hose is held firmly in place as the washer drains or you could flood the laundry room.
For proper drainage, the hose must be at least 6 inches (15 cm) higher than the drainage outlet on the back of the washing machine.

If you need to do some laundry and the permanent washer drain isn’t installed yet, you can use a nearby utility sink drain instead. In order for the washer to drain properly, the sink drain must be at least 6 inches (15 cm) higher than the drain outlet on the rear of your washing machine and at least 2 inches in diameter.

To prevent a flood, make sure the hose is secure because washers drain suddenly and with a lot of force.

Can A Washing Machine Water Drain Into Your Yard?

Yes, a washing machine can be temporarily drained into your yard. The water will not harm your yard or garden. However, it’s not a good long term solution and may violate local building codes. If you do it, use a long drain hose to divert water downhill and away from your home.

Don’t drain a washing machine anywhere near the foundation of your home. A standard size washing machine can dump 20 gallons of water per load. You don’t want that amount of water drained close to your foundation at one time because it can cause standing pooled water and erosion.

If you drain a washer in your backyard, make sure the water runs away from the house.
Washing machine water won’t harm grass or a garden in small amounts.
This is not a long term solution.
Use a long drain pipe to divert washing machine water away from the house.

The best way to drain washing machine water in your yard is by using a gray water system. Gray water systems function in the same basic way as a sewer system. Water from your washing machine pours into a main drain and then out of the house. The difference is that instead of the drain running into a sewer, it fills a below ground dispersal system, like a dry well.

The gray water from your washing machine eventually drains out of the dispersal system and into your soil. It’s a very safe and effective way to drain a washing machine without a sewer.

Should Washing Machine Water Drain Into Your Septic Tank?

No, a washing machine should not drain into a septic tank.An average washing machine uses around 20 gallons per load. That amount of water draining into a septic tank would quickly overwhelm the system and overload the drain-field. Once the drain-field is overloaded with too much liquid, it can flood, causing sewage to flow to the ground surface or create backups in toilets, sinks and other drains.

A septic tank is designed to handle sewage. A washing machine should drain into a dedicated gray water system that’s separate from the septic tank.

Washing machines drain too much water for a septic tank.
Draining a washing machine into a septic tank will overwhelm the drain-field.
If the drain-field is overloaded with too much liquid, it can flood, causing sewage to flow to the ground surface or create backups in toilets, sinks and other drains.
Instead of draining your washing machine into a septic tank, use a gray water system.

Septic tanks can easily become overwhelmed by washing machine water. They use approximately 20 gallons of water per load vs the average 1.5 gallons used by a flushing toilet.

Don’t drain your washing machine into your septic tank or you’ll quickly overload it. This can overwhelm the drain-field causing sewage to flow to the ground surface or backup into toilets, sinks and other drains.

How Should A Washing Machine Drain Be Hooked Up?

If your home has access to a public municipal sewer, this is the best way to drain a washing machine. Run a 2-inch drain from the washer directly into the main sewer line of the house. Typically this is a 4-inch diameter pipe. The main sewer pipe then runs underground to the municipal sewer line in the street.

If your home doesn’t have access to public sewer, drain your washing machine into an underground gray water system.

Drain your washing machine into the main sewer line if your home has access to municipal sewer.
If your home has a septic system and no sewer access, drain your washing machine into an underground gray water system.
In an emergency or as a temporary fix, you can drain your washing machine into a utility sink if it has a 2-inch drain.
You can also drain a washing machine into the yard if it runs away from the house.
Do not drain your washing machine into a septic tank.
Washing machine drain pipes should be at least 2-inch in diameter.
Hire a professional plumber to install your washing machine drain.
The main sewer line of a house is typically 4-inch in diameter.
Washing machine drains typically have a p-trap.

The best way to drain a washing machine is into a public sewer system. But if you don’t have access to one, a gray water system is the next best solution. Gray water systems collect water from your washing machine, and other non-sewage drains, and disperse that water underground and into the soil.

Does A Washing Machine Need A Dedicated Drain?

A washing machine needs a dedicated drain with its own p-trap. Typically a washing machine drain is 2-inch in diameter while sink drains are 1.5-inch. However, a washing machine could be on the same line as another drain as long as the main line they both drain into can handle the water-flow. They may also be able to share a vent if they’re close enough together.

When running a washing machine and sink into the same drain line, I use a 4-inch diameter pipe. That 4-inch pipe then runs into the home’s main sewer line or the gray water system.

I recommend hiring a plumber to install your drains. They’ll make sure all your pipe sizes, traps, vents and heights are correct and to code.

Can You Drain A Washer Directly Into A Floor Drain?

You can drain a washing machine drain hose directly into a floor drain. However, the floor drain needs to be at least 2-inch in diameter to handle the amount of water draining from a typical washer. In addition, your washing machine drain needs a p-trap to prevent fumes from backing up into the washer and the drain line requires a vent.

Can A Washing Machine And Sink Share A Drain?

A washing machine and sink can share a main drain line, however it has to be large enough to handle the water flow for both. Washing machines typically have a 2-inch drain while sinks have 1.5-inch. The main drain they share should be larger than 2-inch. Both the sink and washing machine must also have their own p-trap to prevent fumes from backing up and into the drains.

If the washing machine and sink are close enough together, they can typically share a common vent pipe.

Can A Washing Machine And Toilet Share A Drain?

In a home with a sewer system, a washing machine and toilet can share a common main drain. A toilet has either a 3 or 4-inch drain while a washing machine has a 2-inch. The main drain they share must be large enough to handle the water flow from both until it drains into the home’s mains ewer line.

The washing machine drain must have a p-trap to prevent gasses from backing up into the home, but toilets don;t because they have a built in trap. If the toilet and washing machine are close enough together, they may be able to share a common vent.

In a home with a septic tank, the toilet and washing machine can not share a drain. Toilets drain into the septic tank, but gray water created by the washing machine drains into a separate gray water system. Draining the washing machine into a septic tank will quickly overwhelm it, causing sewage to backup into the home and rise to the ground surface.

Summary: Washing Machine Drainage Options

There are two main drainage options for a washing machine, a sewer and a gray water septic system. Both methods have a few pros vs cons to consider.

Sewer Line. Draining a washing machine into a sewer line is the best option. But it only works if your home has access to a public sewer system.

Water from your washing machine runs directly into the sewer along with wastewater from your showers, sinks, and toilets.
The problem with this method is that many rural communities don’t have a municipal sewer system to tap into.
If there’s an issue with the public sewer system, which happens commonly after big storms and floods, you can’t wash your clothes until it’s fixed.

Gray Water. If you live in an area that does not have public sewer, the best drainage option for a washing machine is a gray water system.

A gray water system works just like a septic system, except it’s only for household wastewater from sinks, showers, dishwashers and washing machines, not sewage.
Wastewater is drained out of the house, through the gray water system, and safely dispersed underground.

Temporary Drainage. If you need a temporary drainage hookup for a washing machine, a slop sink is a good option.

Run a drain from the back of the washer into the sink until you can permanently connect the washer to your sewer drain.
Run a temporary drain line from the washer to the area of your yard where your gray water is drained.
Both of these methods can work as short term solutions until you can properly connect the washer drain.

If you have any questions or comments about your washing machine drainage options, email any time.