I am on the 2006 IPC code. Kitchen is on the first floor, full basement below. There is a 4" CI stack serving a bathroom running in one wall. On that same wall, I'd like to install the new sink plumbing, and nearby add a 2" floor drain for the kitchen. (This will be a normal 2" shower drain) In the basement directly below, there is a bar sink which drains into a 2" ABS line that goes into a CI hub and disappears below the slab. About a foot away, there is a floor drain in the slab. I assume these are connected underneath, and then run to the 4" line coming from the bathroom? Venting on the bar sink is currently 1.5" ABS that is connected to an old galvanized 1.5" line above the highest fixture; I assume that pipe rejoins the nearby stack (which does go out the roof) at some point in the wall. So: * existing 2" floor drain - not sure where it runs to, if it is sharing a horizontal pipe run with the bar sink or is entirely separate back to the 4" horizontal line. * existing 2" bar sink drain - I assume this used to be an old laundry standpipe or something, the trap on the sink is a normal 1.5" P-trap but then it's upsized to a 2" line afterwards and goes down through the floor. * new 1.5" kitchen sink drain * new 2" floor drain in kitchen Can I run the two new drains on a 2" line and join the vertical 2" line from the bar sink? Or would it be better to tap into the 4" CI stack? (If I do need to tap into the stack, I'll be having a plumber do it - not about to touch an old self-supporting CI stack myself!)

Thank you so much for your swift and wonderfully detailed response. Your knowledge and experience is a great help to us. First, let me say that our initial gray water system drain setup was just a test to see how it was working before we finalized the system. We had plans to drain into a storage tank system if we exceeded the Tucson, AZ gray water guidelines which are much less stringent than Californias gray water guidelines as a result of AZs restricted supply of fresh water and our states desire to conserve the limited fresh water supply we have. Fortunately, we do not exceed our local gray water guidelines as our gray water is only from one shower and does not run off of our property. If I understand your statement: "if you have a 2" pipe with a ¼" per/ft pitch the maximum distance from the trap weir (the point on the trap where the inverted U section turns horizontal on the output side) to the vent opening may not exceed 2" / .25" = 8" then we are OK as our vent pipe is almost exactly 8 from the trap weir. Im not sure what this means: "Under the Uniform Plumbing Code the maximum developed length of a 2" waste arm may not exceed 5." But since we are under and are within the specifications of - the local Tucson, Pima County, AZ plumbing gray water guidelines it might not matter. Do you happen to know whether there is a limitation on how far we can run the drain before the actual drain opening into the perforated pipe youve proposed? Right now, our run is about 60 from the drain in the shower to the end of the gray water drain pipe. Regarding the vent pipe rise: I can replace the 2 flat vent pipe run with a 45 degree bend then take that directly to the 10 vertical vent pipe. Or replace the tee and this time turn the tee up and set the branch off point from the tee to the vent pipe at 45 degrees instead of (almost) parallel to the ground like the existing one is set. Thanks for clarifying this for me. I believe federal law supersedes state and local law. However, the AZ Department of Environmental Quality clearly spells out the guidelines for using gray water at home in Arizona. I have pasted an excerpt of the guidelines at the end of this posting, along with the web address for the entire brochure. Thank you also for the estimation of water usage per person per shower: "2 occupants x 25gal/person = 50gallons/day" There is nothing else hooked up to this gray water drain system, only this one shower. So 50 gallons/day is about how much water will be going out for gray water irrigation. And this information you gave us is invaluable: "You could then connect your pipe to a perforated pipe, which has a minimum volume of 50gal, but the total overall length of the perforated pipe may not exceed 100. A 3" pipe has a volume of 2.75gal/ft so a 3" line 137.5 long would contain 50gal, however, the length of the line exceeds the maximum allowable length of 100 so you would have to increase the line to 4" diameter. A 4" line has a capacity of 1.53/gal so you would need 50gal x 1.53ft/gal = 76.5 of 4" perforated pipe." This formula will help us calculate what kind of leach field we need based on the length of the run of the perforated portion of the drain pipe. The entire width of our back yard (the part were trying to irrigate) is not much more than 70. Right now, the gray water from a 10 minute shower wont even make it to the end of the temporary test trench I dug from one end of our lower back yard to the other. And the water never even runs off anywhere into the back yard at 102 degree Fahrenheit average daytime / 90 degree Fahrenheit average evening temperature the water doesnt even sit in the trench very long. What doesnt get absorbed into the dirt right away evaporates pretty quickly even in the evening. So I feel confident that were not going to exceed the basic requirements from our local and state laws. The local plants and critters (lizards, ants etc.) are having a great time at our new back yard oasis though! My wife and I really want to thank you for all your time and for sharing your knowledge and experience. The information you provided will help us set up our gray water system so it is safe, efficient and environmentally sound. Thank you very much again. Here is the information I mentioned earlier: http://www.azdeq.gov/environ/water/permits/download/graybro.pdf The basic requirements to use gray water at your home are simple: Residents must adhere to the guidelines for a Reclaimed Water Type 1 General Permit. A Type 1 General Permit requires no formal notification to the department, no review or design approval, and no public notice, reporting or renewal. Although you dont have to apply to receive a formal permit for permission to use gray water, you must abide by the 13 best management practices (BMPs) listed in this brochure, which were developed to protect public health and water quality. Permit Eligibility and Usage Requirements The general permit is meant for private residential use only. Gray water must be used on the site where it is generated. The area of use cannot be accessible by the public. Under this general permit, gray water can only be used for irrigation not for dust control, cooling or other water uses. Only drip or flood irrigation with gray- water is allowed. Spray irrigation is not permitted due to the potential for inhalation or drifting off-site. Gray water flow must be less than 400 gallons per day. In general, no city, town or county may limit the use of gray water if the use is allowed by this general permit (ARS §49-204). For a copy of the gray water rule, call the nearest ADEQ office or download it at: www.azsos.gov/public_services/title_18/18-09.pdf. The gray water rule can be found in Title 18, Chapter 9, Article 7.

We had basically what looks like white yogurt that was almost filling our shower drain. I tried all of the commercial drain openers to no avail, including the slow-drain enzyme cleaners. Of course, I also tried vinegar, bleach, ammonia, and so on. (By the way... don't ever believe that combining vinegar and baking soda is a remedy to anything. It's a fun chemical reaction and seems like it's doing a crazy good job but what it's actually doing is nothing. Soda neutralized vinegar and basically turns it to water. So it's pointless.) Anyway, I had the same fear as many others have posted about what the rest of the pipes must contain. So I search around and found a couple references to the bio-slime, most of which didn't include a white version, but they seemed to be the closest resemblance to my drain problem. All of them talked about bacteria and fungus. You know what kills bacteria and fungus? Vitamin C. Yep. Otherwise known as ascorbic acid, you can buy it in powdered form and in various volumes. I thought it was worth a try so I ordered a 5 lb. bag for 30 bucks. You may be able to find it cheaper if you can find a non-consumable one somewhere. The process I tried was to wait until the water had drained after a shower and apply just enough to cover the white slimy stuff I could see and just let it sit there until the next shower. When I looked at it the next morning, I was happy to see that (even though it looked awful) the white stuff was turning yellow and drying out. So apparently this was killing it. I kept that process up for 4 more days. Toward the end of those days, I was adding a just a small amount of water so it would carry the powder down into the pipes. End result: It worked! I no longer have the white slime build-up. I only used about half of the 3 lb. bag so I'm ready if the blob attacks again!

When I installed a Dreamline pre-fab shower base, the directions were to leave an opening in the concrete that had about 3-4" open around the drain pipe. I got the pipe aligned as well as I could, and then set the base in place and pivoted/moved the trap and pipe slightly so it would line up with the hole in the shower base. We then cemented the pipe joints so they would stay in place and the pipe would stick up through the hole in the base. When we set the shower base it had thinset under it to keep it level and supported, but directions said we did not need to fill in the area around the p-trap with cement. That part of the base was reinforced and it was just left with a base of sand. The drain fitting in the shower base was installed before it was set in place, and as we set the base in place a rubber collar slipped over the 2" pipe that stuck up from the P-trap. There was a threaded inside fitting on the flange in the base, and as you screwed the fitting down with a special tool (supplied) it expanded the rubber collar so that it fit tightly over the PVC pipe. Then we trimmed the top of the PVC pipe and popped the decorative grill into the drain. My point in explaining all this is that if you use a similar design shower base, and you have a 2" drain line, you would only need to jackhammer a small section of concrete out to install a 2" P-trap, and would only have a very small section of concrete to replace. However, if the shower drain pipe is 1.5", you have a lot more work to do if you want to meet code. Bruce