I'm trying to finish my basement, and the plan includes installing a 3/4 bath with toilet, shower & sink. The house is only 7 yrs old but absolutely no thought was given to finishing the basement when built so there is nothing in place, I'm doing it all. The main drain line for the house comes down in the middle of the basement and crosses the space to the front of the house while positioned between the 1st floor joists (will be in the ceiling of the basement once finished), then drops down along the front wall and out through the basement wall approximately chest-high. Since my basement plumbing will be below that level, I plan to use a macerating toilet with built-in pump to lift the discharge up to main drain line. Problem: how do I connect vent lines, since the only thing I have access to is the main drain already carrying waste? Except for the ~3 ft drop along the front wall, all of the drain is up against the basement ceiling/1st level floor. I've been told by a friend that it has to been vented to the atmosphere but the vent also has to be above the ridgeline of the roof. Obviously, there is already a vent stack in place for the existing plumbing, but the only bathroom on the 1st floor is the opposite end of the house so all associated vent lines are hidden in walls far away from my working location (my house has 1/2 basement and 1/2 crawspace, that end of the house is crawlspace so putting the bathroom on that end wasn't an option). There is a second floor bathroom on the same end of the house as my basement bathroom, and the existing vent stack is somewhat close to that one, but it doesn't even line up with any walls on the 1st floor so I have no idea how they are connected or how to find out where the vent line is located. Even if I can figure out the vent's location, I'm positive it's nowhere near my basement bathroom so running a new vent line from the basement to tap into the current vent stack would require cutting into multiple (exterior) walls on two floors. If I have to do all that, I'll just scratch the bathroom idea and make it a storage closet. Please tell me there is a way to properly vent all of this without having to do a bunch of work upstairs! Thanks for any guidance

Hi FlyNavyP3

In most cases, the macerator pump has a vent as well and that vent can connect into the bathroom plumbing vent, so that is good news for you, i.e. at least you don't need a dedicated macerator pump vent!

In your situation, you need to find a way to get a vent up to that 2nd floor (closest) or run the bathroom vent and connect into the first floor vent (farther). If you choose to run the vent up to the 2nd floor, you may be able to run the vent up through some closets. Here, if you keep the vents forward to the closet and tight into a corner, you wouldn't even notice them as they run up to the 2nd floor or into the attic where they can connect into the main vent stack. If you choose to run your vent to the 1st floor bathroom, you may be able to connect into the 2" lavatory vent (or 2" toilet vent) at a minimum of 42" off the floor....must be a 2" vent for this to work.

Start looking for ways to run the pipe up through some closets... this can work pretty well. In some cases, we have even run the vent pipe up through a closet on the back wall and then boxed out the vent with a soffit box. Just another option.

Post back with your thoughts.

Mark

Mark,

Thanks for the feedback. After reading your response, I may go for option 2. On the first floor at that end of the house there are only two rooms; office in the front, living room in the back. No closets to hide in, and the wall that separates the two is roughly above the bathroom but doesn't line up exactly which means I would be fishing for a path to feed the vent line through, then I would still have to cut into drywall to tap in behind the 2nd floor bathroom or connect in the attic. If I run a vent to the 1st floor bathroom on the other end of the house I can do the long work through the ceiling joists of the basement (pain in the rear, but I can do it) and just have to tear out enough drywall to access the vent in the wall of that bathroom. I was hoping to keep all the work in the basement and avoid creating more work for myself upstairs, but it doesn't sound like that's possible if I still want the bathroom. If I understood you correctly, I can connect the shower, sink & toilet vents all to one vent line and just run the single line? You mentioned the requirement of a 2" vent line for this option; are there any other limits/requirements I should take under consideration, i.e. any distance limits, etc? The holding tank/pump has a built in 1 1/2" vent connector, so I'm assuming I can just use an adaptor to open it to 2" and go from there?

I'm obviously benefiting from your extensive experience, and I sincerely appreciate it. Thanks so much!


Luke

Hi Luke

Determine if WET VENTING is allowed in your state and post back with the answer... could save you time and money if it is allowed.

Mark

Mark,

I did some exploring on the internet, best I could find was Indiana plumbing codes for 2012 (I don't know if they are still in effect or have been superceded). Based on that code, wet venting IS allowed with some restrictions:
[FONT=TimesNewRoman][SIZE=2][FONT=TimesNewRoman][SIZE=2]SECTION 909 WET VENTING
909.1 Wet vent permitted. Any combination of fixtures within two (2) bathroom groups located on the same floor level are permitted to be vented by a wet vent. The wet vent shall be considered the vent for the fixtures and shall extend from the connection of the dry vent along the direction of the flow in the drain pipe to the most downstream fixture drain connection to the horizontal branch drain. Only the fixtures within the bathroom groups shall connect to the wet-vented horizontal branch drain. Any additional fixtures shall discharge downstream of the wet vent.

909.2 Vent connection. The dry vent connection to the wet vent shall be an individual vent or common vent to the lavatory, bidet, shower, or bathtub.

909.3 Size. The wet vent shall be of a minimum size as specified in TABLE 909.3, based on the fixture unit discharge to the wet vent. (TABLE 909.3 didn't paste)

I don't speak "code," but it looks like wet venting is only available for 2 bathrooms on the same floor, which would cancel my basement bathroom (am I mis-reading?). The next section may have bearing on my situation as well:
[FONT=TimesNewRoman][SIZE=2][FONT=TimesNewRoman][SIZE=2]
SECTION 910 WASTE STACK VENT
910.1 Waste stack vent permitted. A waste stack shall be considered a vent for all of the fixtures discharging to the stack where installed in accordance with the requirements of this section.

910.2 Stack installation. The waste stack shall be vertical, and both horizontal and vertical offsets shall be prohibited. Every fixture drain shall connect separately to the waste stack. The stack shall not receive the discharge of water closets or urinals.

910.3 Stack vent. A stack vent shall be provided for the waste stack. The size of the stack vent shall be equal to the size of the waste stack. Offsets shall be permitted in the stack vent and shall be located at least six (6) inches (one hundred fifty-two (152) millimeters) above the flood level of the highest fixture and shall be in accordance with section 905.2.

910.4 Waste stack size. The waste stack shall be sized based on the total discharge to the stack and the discharge within a branch interval in accordance with TABLE 910.4. The waste stack shall be the same size throughout the length of the waste stack.
[/SIZE][/FONT]
[/SIZE][/FONT]I don't know the technical definition of a "waste stack" but was wondering if that would apply to the vertical portion of the drain (approx. 3 ft) that drops down from ceiling height to the main drain pipe that exits the basement wall and goes out to the street? What do you think? Do these give me any options?

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[/SIZE][/FONT]

Any combination of fixtures is the key phrase here as it pertains to your job. In this case, you could wet vent one or two bathrooms, but no more than 2 bathrooms so you are good to go.

To wet vent a bathroom, you simply take a 2" vent off the toilet drain (roll center of fitting above the centerline of the drain) and then run that 2" vent over to the sink. This 2" vent/drain will come above the floor and pick up the sink with an 2"X1.5" tee fitting. The 2" vent will continue upward and pitch up toward the upstairs vent and connect there.

The 2" shower drain simply connects in between the toilet and the sink underground. Here, all fixtures use the same 2" vent... pretty nice, huh? See image below.

The macerator vent can connect into the 2" vent anywhere above 42" above the floor.

Make sense?

Attachment 47805

Fly Navy,
All but a handful of states have adopted the 2012 IRC & 2009 IPC. Each allows wet venting, and, a bathroom group can be vented with a 1.5" pipe, as long as there is a continuous 3" ( or larger ) vent somewhere in the residential structure. The goal of the IPC & IRC is to provide a uniform code that provides broad based principles to include new technology, the use of new materials, and evolving building design. Uniformity makes it simpler for professionals & homeowners to comply safely & effectively, and, uniformity provides a baseline of compliance for code officials to enforce no matter the jurisdiction. Check with your building department to determine which code authority they abide by.
It is much easier to route a 1.5" vent, and comply with the requirements for drilling & notching the framing. Slab & underground Dwv piping should be a minimum 2" diameter. Sewage ejector vents are sized based on the GPM of the pump - 1.25" is the minimum vent size allowed based on a 10gpm discharge rate.

That's great info. Mike. As you know by my name, I'm in Massachusetts and we still have our own specific codes, but I've heard most states have adopted the IRC and IPC codes. If Indiana has adopted the codes then FlyNavy certainly lucks out, 'cause as you said, it is simply easier! However, FlyNavy doesn't need to worry about the sewage ejector information... he's installing a macerator toilet and in most cases a macerator system vent can connect directly into the plumbing vent.

Mark

Thanks, Mark, I didn't mean to confuse the two pump systems - I hope I didn't mislead anyone. Both can be vented through an existing dwv system; I wanted to point out that the IRC & IPC are more lienient in their allowances for vent sizing and connections.. .

I'll tell you this. It would be nice if MA adopted the code... really is a strict code here that just goes too far sometimes! Have a good day!