I have a washing machine upstairs. The discharge hose is placed in the top of some 2" ABS pipe. That pipe then drops about 14' to my basement floor, then runs along the floor for 5', ending in a hole in the floor. (The house is from 1955, so that hole in the floor is almost certainly intended to be used as a washing machine drain).

When the washing machine empties, the water properly flows through all the pipe and into the drain. Eventually though, the water starts to back up onto the floor. The floor is sloped towards the drain, so this isn't catastrophic, but I'm wondering if there is any way to reduce the flow rate of water entering the floor drain?

I've considered:

  • increasing the pipe to a 4" or 5" pipe, then reducing the pipe at the drain end down to 1/2" or so - using the pipe as a sort of basin.
  • Emptying the pipe into an actual basin that can hold the water, then having a smaller hose/pipe drain from that basin into the floor drain. Pretty much the same as option #1.

Any other suggestions? Is there any way to change the rate at which the washing machine pumps out water? I think if I could cut that in half, the problem would be solved.

  • 1
    Snake the drain to improve its flow rate?
    – gbronner
    Sep 10, 2014 at 4:52
  • I'm going to do that, but the drain can only get so clear. Sep 10, 2014 at 6:14
  • 1
    An all important question: where does the water go next? Sewer? Leach? How many inches slope might there be?
    – Bryce
    Sep 11, 2014 at 5:29

5 Answers 5


Well... you've got 22 gallons coming out of the washing machine each cycle. You've got about 2 1/2 gallons in the vertical pipe, and another gallon in the horizontal pipe, so you'd need to store another 20 gallons to be reasonably safe if you go down that route. I wouldn't advise it -- drain water has all sorts of junk in it.

Personally, I've never heard of a floor drain that is 2" or less, so your drain should have sufficient capacity to drain the water thrown off by the washer.

So it sounds like there's some back-pressure causing the water not to flow through the drain pipe as fast as it should. I'd start by snaking it, and if that doesn't work, I'd extend the PVC pipe through the hole and fairly far down the drain; this should reduce the pressure drop and force the water through the drain faster.


Is your drain flowing to a septic tank or to a sewer line?

Do you have a boggy area in your yard where the drain is emptying? That could mean you have a broken, collapsed drain. Is there a moisture problem under the house or along the foundation?

It may be time to install new drains from the house to accommodate the water flow of the modern house. In 1955, washers were not meant to carry the amount of water we use now. In fact, in 1955, my mom was using a ringer washer on the back porch. The washer hose drained to a trench in the yard.

Do you have any problems with any other drains in the house?

I will say, that for many years I had a garden hose attached to my washer drain hose with a radiator clamp, ran the garden hose out through a slit in the dryer hose and vent, sealed the slit with duct tape. I laid the garden hose where I wanted plants and trees to be watered by the wash water that day. This "grey water" recycling made my yard lush and cut the costs of watering my yards. The only drawback to that is that during freezing weather, I had to wait until the hose thawed. Since I was living in Mississippi, and later in South Carolina, most times we had slight freezes, the hose thawed each afternoon after an overnight freeze. So...if you do need to make new drains, you could drain the washer with a garden hose clamped to the washer drain, until you got the new drains connected. Wishing the best for you.

  • The drain then flows into my main sewer line which goes out into the city's main, etc. There is no moisture problem that I know of - if the main is collapsed (which is a possibility I suppose), it's not right against the house. Sep 11, 2014 at 14:05

Bonus: your laundry is on the 2nd floor? Great. You're lucky. Install a laundry to landscape system, where that drainwater goes through new piping directly to a landscaped area outside, preferably one involving shrubs and/or trees.

You can install a two way diversion valve for seasonal use, or messy load use.

Some jurisdictions give automatic permits for this, to encourage such installations. Others may be unfriendly to any gray or grey water system.

  • ... Or perhaps into a "rain barrel" so you can decide later when and where you want to water the plants?
    – keshlam
    Sep 11, 2014 at 12:52
  • 1
    I'm in Alberta, Canada, so the pipe would be frozen for half the year. Appreciate the suggestion, but it's not practical where I live. Sep 11, 2014 at 14:06

So the washing machine is draining into the basement floor drain? Sloppy solution. What's that draining into? Is it routed to a sump (with or without pump), the septic drains, some other leach field, the ravine behind the house...?

Normal setup goes directly into the septic drains, just as with any other sink or bathtub. The question is why whoever kluged this didn't do it that way -- which may simply be that they were excessively cheap.

  • That drain is the beginning of the main sewer drain into the city's main. Sep 11, 2014 at 14:06

I had the same issue. I swapped the clothes washer hose with a dishwasher hose. The clothes washer hose was 1" but the dishwasher was only .75", that restricted the flow & forced the pump to slow down. The dishwasher hose fit easily onto the clothes washer without any modifications. The repair took 5 min & completely fixed the problem.

The wash cycle takes a couple extra minutes because it drains slower, but everything still works normally. I'm nervous it might be harder on the motor & cause the machine to die early, but I decided it was worth the risk.

I'm also considering switching from a top loader to a front loader because front loaders use less water.

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