You stated you just bought this house but you did not mention the age of the house itself. Prior to WWII it was common to use cast iron pipe for all DWV piping 2" or greater while the 1-1/4" & 1-1/2" lines were commonly run with lead pipe, galvanized iron pipe, brass pipe and copper pipe. In residential construction the use of copper DWV pipe in sizes greater than 1-1/2" is extremely rare although not unheard of in fact there are some municipal codes today that do not permit plastic pipe(ABS or PVC). If PVC is approved in your area you may cut a section out of the copper line and insert a Wye. (A santitary Tee is prohibited on a horizontal pipe). From the side opening of the Wye you would then install a "Street 1/8th bend" to complete a 90deg connection. A street 1/8th bend would be a 45deg elbow with a female hub on one end and a male raw pipe size on the opposite end. The side opening of the Wye would be comming off at a 45deg angle and the 1/8th bend adds another 45deg to give you a 90deg intersection. The purpose of this is to direct the flow in the downstream direction without disrupting the velocity of flow. (There is also a fitting called a "Combo" which is a Wye & 1/8bend ready made in one fitting which would be approved for use here.) If you are under the Uniform Plumbing Code(UPC) you may run a line up to 8' measured on the pipe from the main drain to the closet flange without adding additional venting. If you are under the International Residential Code(IRC) and if your new line will be serving only a watercloset (toilet) it may run and indefinite length without requiring additional venting. You may use rubber Fernco connectors to make the transition connections between the PVC and Copper lines. All lines 3" or less in diameter require 1/4" per foot pitch. (under extreme conditions a 3" line may be run with a 1/8th inch per foot pitch but it requires the expressed written permission of your inspecting authority")

Thanks for the feedback. I will actually have 2 new water closets on the second floor, however, I thought that it would be simpler to separately drain and vent all the fixtures that are on the side wall of the house (opposed to the back wall that I show above). My working plan for the side wall is this. I was planning to use 1 1/2" pipe for all the vents except for the main stack where I was going to use 3" for the vent. I tried to annotate the picture with the size of pipes. Is 1 1/2" ok for all the vent pipes? Is 3" overkill for the main stack vent? Any other problems that anyone sees with this plan? Thanks for your help.

Once again Snappybob has allowed his frustration to force him to talk through his hat. Contrary to his opinion the unions have very little to nothing to do with the high cost of plumbers. In fact, on a national average the plumbers union represents less than 30% of all working plumbers. The real reason the cost is to high is because certified plumbers are becoming scarcer every day. According to the U.S. Department of Labor plumbers as a whole are currently in critically short supply. Add to that the fact that 65% of all licensed Master Plumbers and 44% of all licensed Journeyman Plumbers are within 7 years of retirement and we start to see the problem. Now before you blame the apprenticeship program for failing in its obligation to train new plumbers ask yourself, what does it take to become a Journeyman Plumber? First the candidate MUST BE enrolled in a state approved and supervised apprenticeship program however 65% of all the candidates who apply for the apprenticeship program fail to pass the mandatory prerequisite entrance exam because they cannot do basic high school level math. Of those who do pass the exam, they are enrolled in the state apprenticeship program and agree to work under the apprenticeship program guidelines under the supervision of a Master Plumber for a period of 4 years. In turn, the state apprenticeship program lists a number of different categories for both residential and commercial such as Sewers & Septic tanks, Lift stations, DWV, domestic potable water supplies, potable water distribution, non-potable water distribution, liquid or gaseous fuels, chemical piping, high pressure air & medical gasses. At the end of each workweek the candidate must submit a timecard to the state apprenticeship board outlining the number of hours worked in each category for the week. Any workweek with less than 40 hours does not count and any candidate who looses more than 4 workweeks in a calendar year for unexcused absences is dropped from the program but that is rarely a problem because during peak season they will average 60hour weeks and rarely will they ever get a true 40hour week. On top of that, each candidate is required to be enrolled in a college or technical school training class and attend two 3hour evening classes a week. Cut two consecutive classes or three classes in one semester and they are dropped from the program. Minimum passing score on exams is 70%. Needless to say, the dropout rate is about 60% the first year, and on average only about 8% of those who enter the program actually finishes the full four years. Once they have completed the four-year programs each candidate receives a Diploma from the school and a Certificate of Completion from the state apprenticeship board certifying that they are now a plumber. With those two documents in hand along with a written letter of recommendation from the Master they trained under they may then apply to sit for the state-licensing exam. In Florida, where I took my training they have an open book exam. When presenting yourself for the exam you must pay a $250 non-refundable fee plus you must have in your possession a list of books outlined by the examining board. The books cost $600 and you must have the latest editions because they constantly upgrade the exam to the latest books. There is a 60% failure rate for those taking the exam the first time and on average it takes three attempts to pass the exam. Oh yes, did I mention that during the apprenticeship program whenever we introduce a new technique to the student we issue the necessary personal tools to perform the task, with the understanding that the tools will be paid for by the student through a payroll withholding. Big deal you say, so they buy a few tools. Well consider this, a 36" Rigid pipe wrench is $45 and when all is said and done each student will purchase about $2k in tools. On the other hand, when the students enroll in the program they sign a student load for the $7k tuition however, if they drop out the student loan in on them but if they complete the program the employer pays the tab. Now before you carry on about greed let me ask you this; Did you work 40 to 60hrs a week digging ditches, toting heavy materials and working outdoors under all weather conditions while attending college? Did you have to purchase all your own tools for your job? Did you even pay off your student loans, assuming that you actually attended college to get your job? Dont get me wrong. I dont begrudge one minute in this trade, in fact if you have what it takes I would highly recommend any young person starting out to strongly consider Plumbing. Where else can you find a job that cannot be out sourced to the Pacific rim, get your education paid for and start out at $30 to $50k a year with the potential of becoming a Master Plumber who makes $125 to $250K per yr?

Hey All - Holy cow! Sorry... I'm not usually so dismissive - in fact I'm surprised I "ignored" everyone's comments as it appeared I did (although I did read and appreciate them, honestly - I just must have gotten distracted and either fallen asleep at my laptop which is sadly common (Queen of TMI) or else run off in a hurry! Easy to do with 3 kids underfoot. It probably sounds like I'm just making excuses...). What I failed to mention is that I'm in freak-out mode over here with yes leaking pipes, and this is in fact a coincidence. Our bathroom's above our dining room (well sits above part of the kitchen and part of the dining room) and the beautiful old unpainted wood above the swinging dining room door (leading to kitchen) is dripping onto the floor slowly. It's causing the wood above the door to expand and now the door won't close without rubbing. I'm worried about the beautiful wood and the moisture underneath (don't want rotting). I wouldn't be as concerned if it were painted - though would still be concerned of course. So I've seen 4 plumbers and the most reputable of them have said - after examining closely (we even have a big hole in our bathroom floor from previous owner leaving it that way after a plumbing repair, so that's helped them see more - including the fact that that ring under the toilet is dry) - that it's time to replace it all. There's some question as to whether the drain pipes are necessary and a lot of testing has been done by them to evaluate what's going on. But because our tub and sink drain so terribly anyway and things look shoddy (lots of evidence of past repairs), we've been advised to put new stuff in. They can also start with the supply lines and see what they see when the get up in the walls to do that and possibly just do that. What's funny is that I asked him to do your flushing thing Bus Driver and he went up there to do a few things including that - and I heard the toilet flush even - but now I can't remember what he said (blush)! I get way spacey when I feel overwhelmed... I apologize for acting so ungrateful and inconsiderate. Damn. The cost of plumbing alone (various bids and options depending on what we want to do) isn't as bad as I thought it was - not that it's going to be easy - but the demo and patching is where I have no idea what to expect price-wise (am waiting to hear back from people - just left messages). And if we rip out our lovely old floors :( it'll cost a fortune. Hoping to just find close-enough matching hexagonal tile and patch in...but I digress. Ha - great - meanwhile a lil' sprog has just come down from bed so I'm signing off YET AGAIN to get him down but will come back later. Thanks. and sorry again for my rudeness.