What is the standard size for a washing machine drain pipe?

Author: Buford Rau  |  Last update: Monday, February 9, 2026

The standard washing machine drain size is 2 inches, and the minimum requirement is 1 1/2 inches. Modern washers typically require a larger drain, and you may need a larger drain if it's connected to your kitchen sink.

What size is a washing machine drain pipe?

Answer: The minimum 2-inch drainage pipe is used for the standpipe, trap, trap arm to the vertical vent or waste stack and also for the vertical vent. As soon as the drainage pipe turns horizontal from the vertical vent or waste stack, the minimum drain pipe size for the horizontal drain is to be 3 inches.

Can you use 1 1/2 inch pipe for a washer drain?

The drain pipe should be a minimum of 1-1/2" I.D. (inside diameter) to ensure proper draining. The Washer drain hose is a 1-1/4" O.D. (outside diameter). To be confident that no siphoning of water will take place, the drain plumbing must be a minimum of 30" high for Top Load Washers.

What is the diameter of a washing machine waste pipe?

Washing machine / dishwasher waste outlet / drain hose pipe, sold by the metre (max 10m). Inside diameter approx 19mm.

What is the code for a washing machine drain pipe?

406.2Waste connection. The waste from an automatic clothes washer shall discharge through an air break into a standpipe in accordance with Section 802.4. 3 or into a laundry sink. The trap and fixture drain for an automatic clothes washer standpipe shall be not less than 2 inches (51 mm) in diameter.

How To Install a Washing Machine Drain Stand Pipe - 2" Trap & Stand Pipe Height

What size is a washing machine water pipe?

3/4 inch BSP threaded connection (standard washing machine hose thread).

Are all washing machine drain hoses the same size?

Washing machine hoses can vary in terms of length, shape, and material. Some hoses have straight ends, while others have a 90-degree elbow on one end so that the hose fits snugly against your laundry room wall. But they have one thing in common: they all sport ¾-inch female threaded fittings on both ends.

What is the diameter of a drain pipe?

Land Drain Pipes

In both perforated and unperforated coils, lengths of 25m and 50m are available in 5 diameters to allow installers to dictate in part the rate of water flow. Land drain pipes are available in 60mm, 80mm, 100mm, 160mm and 200mm diameters.

What is the washing machine drain pipe called?

A washing machine drain pipe, also known as a drain hose, is a flexible tube used to expel used water from a washing machine to a dedicated drain system. The washing machine drain pipe is an essential component of any household laundry system, ensuring efficient and safe removal of water post-wash.

How do I know what size drain pipe I need?

What Is The Right Size Pipe For Your Main Sewer Line?
  1. Toilet drain pipes are usually 3 inches in diameter.
  2. Washing machines and laundry sinks generally need 2-inch drain pipes.
  3. Shower and bathtub drain pipes are usually 2 inches in diameter.
  4. Sinks usually require a 1.5-inch drain pipe.

What is the standpipe code for a washer?

804.1 Standpipe Receptors.

No standpipe receptor for a clothes washer shall extend more than 30 inches (762 mm), or not less than 18 inches (457 mm) above its trap.

What pipes do I need for a washing machine?

Usually, a washing machine has hot and cold water pipes extended with T-fittings to reach its supply hoses. Mini stop valves allow you to isolate the machine without having to cut off the water supply. Hook the waste hose into a standpipe with a P-trap. A dishwasher normally just has a cold water supply.

Does a washing machine drain need an AP trap?

Install a P Trap

A P trap is a necessary part of the plumbing for a washer. It's a U-shaped piece of piping between the appliance and the sewer line. After water drains out of the washer, the P trap's shape holds enough water to create a barrier between the house and the sewer line.

How long should washing machine waste pipe be?

Ideally you should extend the plumbing to the appliance, for both water supply and drain waste. But if absolutely necessary you can extend your waste drain hose to a maximum of three (3) metres, providing the use of the correct bore size, type, and quality of hose, and suitable joining pieces are employed.

What is the common drainage pipe size?

The 90mm and 100mm are the common sizes of downpipes in most houses. If you are adding another one to your existing set, I suggest using the same size already installed in your house. The 100mm is more often used in underground drainage.

What is the standard size of drainage?

UGD pipe sizes

These pipes are available in 110 mm to 315 mm with different stiffness classes. Larger diameters are typically used for main sewer lines, while smaller sizes are suitable for branch lines and residential connections.

What is the code for a washing machine drain?

According to the Universal Plumbing Code, the standard drain size for a washing machine is 2 inches. The absolute minimum should be about 1 1/2 inches. However, keep in mind that wash load capacities can vary by up to 400% or more depending on the model.

What is the diameter of the washing machine waste pipe?

Inside diameter of approx 19mm. Good plumbing installation practice with regard to fall, support and siphoning should be observed and the specific instructions of washing machine / dishwasher manufactures should be applied.

Can a sink and washing machine share the same drain?

Yes, with a Y-fitting, you can successfully connect a utility sink and washing machine to the same drain.

Can you replace washing machine drain pipe?

If your washing machine drain hose is leaking, split, torn or damaged, your washing machine won't be able to drain or function properly. As such, the drain hose will need to be replaced to get your appliance working properly again.

Are all washing machine pipes the same size?

Drain hoses for domestic washing machines and dishwasher's are generally universal but the end fitting that connects to the machine sometimes differ. there are a number of differing “cuff” diameters (19mm and 22mm) but these can often be purchased separately and fitted to a length of hose.

How often should you replace a washing machine drain hose?

Regardless of their condition, washing machine hoses should be replaced about every 5 years to prevent a flooding emergency. Standard washing machine hoses are made of black rubber. Unfortunately, these hoses only last a few years and will eventually fail, causing one big mess and costly water damage.

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