I have a shop in a small industrial unit and I want to put a washing machine in my bathroom between the toilet and the sink. How can I add a drain for it? See attached drawings.(Yes that's my graphical depiction of the sink and toilet)
Thanks

Love those graphics! However I can see a problem with the shower. Because if the high rate of discharge from the washer and the shower being the low spot bin the system the least little bit of back pressure would divert the washer discharge back into the shower,
How ever, this is doable. You can revent the washer vent back into the lavatory vent using a inverted sanitary tee.
I'd fell better if you could move the shower drain upstream from the washer but it you get some back up from the shower you could always add a check valve on the shower drain line, Good luck, Tom

Hi Tom,
Thanks for the response. One thing missing from my graphics is the cement floor! I'm trying to avoid having to cut into that. Is that possible? I had a combination washer/dryer there before and had it drain into the sink. The sink had just enough capacity that it wouldn't overflow, but, it was kind of crude. The machine only lasted about 3 - 4 years, and they're so expensive that I thought I'd just install a regular machine. The combo machine only required a cold water line, it heated the water itself, and it didn't require a vent for drying. But, I paid $600 for it brand new and replacing it will cost at least $900 with the better ones about $1600.
I prefer to install a regular washer, I can easily connect to the hot water supply and I can put an electric dryer in the garage area.
Can I tie into the existing drain underneath the sink somehow?
I appreciate the advise.
Richard
By the way my graphics also don't show a vent for the toilet, but undoubtedly there is one.

NOPE! Good try! I realize what you're attempting to do but it just won't fly, We put washer traps as close to the floor as possible for a reason, Any idea how high your stand pipe would have to be? If you want a washer between the toilet and the lav you're going to hafta cut into the main and roll a combination wye and eight on its back up to sanitary tee where you can install the trap, standpipe and vent. Good luck, Tom

Pictures of the waste stack under the sink are attached. Could I connect up to the cleanout? (I hope)
I'll send a picture of the washer showing the drain hose.
Also, do the water supply line valves have to be mounted at the height of the machine, or, is that just for convenience?
Thanks for the help(I sure need it!)
Richard

Picture of the washer showing drain hose

Is the cleanout setting next to the floor or is that a shelf I see under it. How high off the floor is it? If it's setting next to the floor you came come out ot the tee with a adapter and convert to PVC. Back to you, Tom

That is the bottom of the sink cabinet. The cleanout is about 6" off the floor. So, I can come out of it with an adapter and convert to pvc? Oh man, what a relief! Thank you, Tom. I will most likely be seeking your advice again.
Thanks,
Richard

Yeah! Ya lucked out. With both the drain and vent already in place all you're going to need is a sanitary tee . A trap and a 36" stand pipe, Good luck, tom