Kitchen sink and clothes washer on the same 2" waste branch

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Ken Harvey

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New kitchen sink 25' from clothes washer.
Existing clothes washer with 1 1/2 trap.

Can these two share the same 2" horizontal drain line? note there's an 8" drop from the sink line half way to the washer, so not continuously 1/4 per ft.

Will inspectors say the existing washer is not grand-fathered and therefore insist on at upgrade to 2"

Even with the upgrade, dfu's total 5, so less than the 2" pipe's 6dfus. Was told by a pro that the sink needs a separate line all the way to the 3" stack, but I don't see that in 248CMR.

Tuttles Revenge

In the Trades
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I'm not in that state and not sure what code that is, but reading through a bunch of it... its goofy.

I don't see anything in UPCODE that says that a clothes washer and kitchen need to upside to 3". We recently had an inspector in our area which uses UPC say the same thing and have to retract it.

The only place I found a reference is this chapter:
(b) Kitchen Sink Wastes (Domestic). 1. Not less than a 1½ inch branch waste or waste outlet shall be provided to receive the fixture drain from a kitchen sink, which shall connect independently to the sanitary drainage system. 2. A kitchen sink shall not waste into any horizontal drain line that receives the waste from a bathtub or similar flat bottom fixture that is smaller than three inches in diameter. (*is this what people are referring to? That doesn't even make sense. Are they inferring that plumbing systems don't work where tubs and kitchen sinks come together? I don't see how this refers to clothes washers however)

TABLE 1 MINIMUM SIZE OF FIXTURE TRAPS Plumbing Fixture Trap Size in Inches Clothes washer (domestic) 2 (*inch)

(12) Automatic Clothes Washing Machine. (a) Water Supply. The water supplies to clothes washers shall be protected against backflow by the use of an air gap or a back flow preventer. (b) Waste Discharge. 1. Domestic Machines. a. The waste from a clothes washer shall discharge through an air break into a laundry utility sink or standpipe. b. The standpipe shall extend to a minimum height of 30 inches above the base of the machine and shall not be less than 1½ inches in diameter.

(e) Domestic or Culinary Fixture Prohibited as Receptors. No plumbing fixture which is used for domestic or culinary purposes shall be used to receive the discharge of an indirect waste pipe, except that in a residence a kitchen sink is acceptable for use as a receptor for dishwashers and portable clothes washing machines.

Automatic clothes washer (2-inch standpipe) 3(*DFU)
Hey, wait a minute.

This is awkward, but...

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