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I am redoing the bathroom in my basement and I have a question regarding the plumbing. As you can see in this pic I have labeled what I believe to be the vent pipes. My question is that circled in yellow is a unidirectional flow valve. Can someone tell me why it is there?

Also in the far corner I have a shower but it has no vent. Is this because it is wet vented into the main soil line?

My plans are to keep the shower where is it but I will have to relocate the drain a few inches over as the new shower is much bigger. As well the washer and dryer will now be on the other side of the bathroom. I will also be moving the toilette to the other side of the room. The sink will remain in the same place.

I just wanted to know if the directional flow valve is necessary for the washer. Keep in mind I will be relocating the drain to the other side of the room which means I will be feeding it directly into the 4" soil line. Of course I will be running a new vent for the washer that will tie into the existing vent that is shown in this picture.

Thanks for the help

I don't exactly know what you call a "directional valve". But that horizontal pipe on left appears to be a dirt-arm (drain) servicing sink. The vertical pipe it runs into is drain bellow the San T, and vent above the San T.

The directional valve is what is circled in yellow. It is a valve that allows water to only flow in one direction

Hi Pare John:

That unidirectional valve or BACK-FLOW valve is sometimes installed to keep sewer from backing up and out the washing machine drain pipe should the city/town sewer back up or should your own home sewer clog up and back up the drain pipe.

It is not something that is absolutely required, but it is not hurting anything by being there (I have never installed one on a washing machine). It could actually be there more as a clean-out then anything. The fact is that if the sewer pipe does back up it may not show up at the washing machine, but it will show up at the sink or the shower so kind of a pointless valve in this situation. If you re-install it over at the 4" pipe, be sure that it is accessible for the future as these valves can fail over time.

Now, in terms of the shower being wet vented, I'll tell you that I am quite confident that you are right about that if those pipes are 2" pipes. If the lavatory vent is a 2" vent that is usually an indication that the toilet and the shower are wet vented. If those pipes are 1.5" then hopefully there is another 2" vent for the toilet and shower behind another wall... hmmm..?

If you will be moving the toilet across the room and the shower only a few inches you will have a chance to see if the shower is wet vented as the shower vent should connect into the toilet pipe around 5-6 feet from the toilet (or closer).

Anyway, if the toilet isn't vented correctly or there is no vent for the shower pop back and let us know.. glad to discuss venting as you need.

Finally, if you will be cutting into the 4" pipe to install the washing machine be sure to support the pipe well before cutting into it (plastic...right?) and consider installing a 2" pipe, trap and standpipe. They also make a great washing machine box that fits behind a wall and virtually hides all insidee the wall... made by symmons (or others)... see picture. At a minimum please change the washing machine water valve to a single lever shutoff as in my last picture.

Let us know if you need more...

MARK

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My question is that circled in yellow is a unidirectional flow valve. Can someone tell me why it is there?

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At one time the previous owner had a backup problem that came up in the washer stand pipe. This back up had to come from some other source then the washer pump as the check valve wouldn't prevent this from happening.
You are correct. The pipe on the is a vent and the washer revents back into it. That check valve troubles me. Is anything else discharging into the vent from above that would cause the stand pipe to back up?

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Also in the far corner I have a shower but it has no vent. Is this because it is wet vented into the main soil line?

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If the shower drain's connected to the lavatory drain line the answer's yes.

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I just wanted to know if the directional flow valve is necessary for the washer. Keep in mind I will be relocating the drain to the other side of the room which means I will be feeding it directly into the 4" soil line. Of course I will be running a new vent for the washer that will tie into the existing vent that is shown in this picture.

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I would leave the check valve off in the new installation.
Good luck, Tom

Oooops... Of course... I somehow missed it first time I was looking at your pic. My apology...

Yes, as Mark explains : it is there to prevent sewer from backing up and overflowing into your laundry. Its presence may indicate sewer problems in the house. If that's the case, than it may bea good idea to leave it there as it is. Do you have frequent sewer back ups?

Thanks for the replies guys.

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Now, in terms of the shower being wet vented, I'll tell you that I am quite confident that you are right about that if those pipes are 2" pipes. If the lavatory vent is a 2" vent that is usually an indication that the toilet and the shower are wet vented. If those pipes are 1.5" then hopefully there is another 2" vent for the toilet and shower behind another wall... hmmm..?

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The vent that you see in the pic is 1 1/2" pipe.

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If you will be moving the toilet across the room and the shower only a few inches you will have a chance to see if the shower is wet vented as the shower vent should connect into the toilet pipe around 5-6 feet from the toilet (or closer).

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Doesn't wet venting mean that there is no vent pipe and that the drain pipe becomes the vent? If that is the case then why would the shower connect to the toilet pipe and not right to the main soil line?

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Yes, as Mark explains : it is there to prevent sewer from backing up and overflowing into your laundry. Its presence may indicate sewer problems in the house. If that's the case, than it my be good idea to leave it there as it is. Do you have frequent sewer back ups?

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In the four years living here I have never had any isuues

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If the shower drain's connected to the lavatory drain line the answer's yes.

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When I move the toilet I will be shortening its drain line. Does that mean I have to run the drain line longer to reach the now shortened toilet line or can I connect it straight to the main soil line and have it wet vent through there?


Also keep in mind guys that the 4" soil line in the basement serves and the waste line for upstairs. as well the 4" soil line in the basement in running horizontal out to the street

Nope.. wet venting is where a fixture connects into a drain pipe and uses a vent from another fixture to vent the first/second fixture.

For example, a toilet and a shower would be wet vented by a lavatory vent... as long as the pipe size increased to 2" (lav. usually only needs an 1.5" vent). The wet vent would be the lavatory drain line... but the VENT is present at all times. Here, it is assumed that people will not be using the lavatory drain and the toilet or shower at the same time so we can use the lav. Vent to vent each fixture. The increase in 2" is because all toilets require a 2" minimum vent.

So, as stated, the toilet needs a 2" vent. It can use the lavatory vent as a wet vent, but again, the vent would need to be increased to 2" to meet code requirements. Here, you can connect the toilet into the main drain, but you would need to run an individual 2" vent for the toilet (connecting it into a 2" vent or larger in the bathroom) or connect the lavatory drain into the toilet drain pipe.

If never had issues with backups... lose the backflow valve... ;)

Let me know if you want to discuss more. I'll be back on later tonight.

MARK

If the toilet needs a 2"+ vent then why are my vents all 1 1/2". Also I have all the bathroom walls open and I see no other vent lines running up.

Could it be safe to assume that it wet vents through the 4" soil line? in theory the 4" soil line is a vent as it is part of the main stack that connect to the main vent on the roof.

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Could it be safe to assume that it wet vents through the 4" soil line? in theory the 4" soil line is a vent as it is part of the main stack that connect to the main vent on the roof.

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Nice try John, But all codes mandate that you can not discharge a major fixture such as a toilet past a unvented minor one. That means that if you have a toilet or washer discharging upstream from your shower the shower must either have it's own vent or be connected to a drain from a fixture the does have a vent. This is called wet venting. But I like your reasoning. Regards, Tom

YUP... like Speedball said... can't discharge major fixture past unvented fixture... could siphon the trap and allow sewer gasses to enter the home... very unhealthy!

The fact that there are only 1.5" vents only means that the work was most likely not done by a licensed plumber, but as we say around here, "an 1.5" vent is better than no vent at all"... ;) SO I figure you are all set here... until you move that toilet!

Let us know if you have more questions...

MARK

Well the house was build in"89 and the bathroom was build as part of the house. So I am really hoping that the plumber was licensed.

What is funny is that the sink and washer drain pipes that come out of the concrete are 2" but are then reduced to 1.5" when the become vents.

I am going to assume that the shower gets wet vented by the washer and the toilet gets vented by the sink. I have lived in the house for 4 years and the downstairs toilet has always flushed ver well. So I am guessing the 1.5" vent is sufficient enough.

A question I have is what is the max distance a wet vent is allowed to be from a fixture. Example that the toilet is vented by the sink vent. What is the max distance that this vent can be when it junctions with the toilet drain pipe?

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Nice try John, But all codes mandate that you can not discharge a major fixture such as a toilet past a unvented minor one. That means that if you have a toilet or washer discharging upstream from your shower the shower must either have it's own vent or be connected to a drain from a fixture the does have a vent. This is called wet venting. But I like your reasoning. Regards, Tom

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From what I see the first fixture that is immediately after the upstairs toilet would be the downstairs toilet.

Obviously I will get a clearer picture of how the plumbing is done once I get the concrete broken up. I will be sure to post some pictures this weekend when I get to this step

Hi John...

I am confident that the washer doesn't wet vent the shower as it is illegal (again, in terms of plumbing code) to wet vent any fixture using a washing machine drain or a kitchen sink... ;)

I'm betting that everything is wet vented by the lavatory even if only 1.5".

The maximum distance for what you are doing will be between 5-6 feet between the toilet and the connection for the lavatory.

Lookin' forward to the underground pics... :)

MARK

I would first like to say that I appreciate all the help that you guys are giving.

I am guessing then that the washer has its own vent and that the sink is wet venting the toilet and the shower. (like you had said)

I will get a much clearer picture once the concrete is broken up


Another question I have is if the main home sewage line and the water main inlet into the house run side by side. Meaning if I know where my water inlet comes into the house from the strre does this mean my sewer line to my house runs beside it?

Not necessarily...

I would have you look around the front of the house and see if you can find a MAIN CLEANOUT to the sewer drain. After you locate the cleanout you want to find the first 3" or 4" waste stack in the house and then connect a straight line between the stack and the cleanout.

Most likely, before the concrete was poured, the plumbers came in and laid a straight shot of pipe between the cleanout and the stack. Of course, hard for me to say without seeing all, but this is how it usually gets done!

Glad to help...

MARK

Follow Marks instructions on locating the house cleanout. Now call the Building Department and ask them for the measurements to the street raiuser,( where your sewer connects to the city sewer). Line the two up and you'll have a pretty good idea of where your sewer line's buried. Good luck. Tom

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Ok guys, got all the concrete broken up and this is what I am finding. I would just like to know if you believe that mu assumption of the vent location to be correct. Also I would like to know if I can put the toilet in its new location and if the vent that is there will still properly vent the toilet.

The reason I am not sure if that is a vent is cause it seems to run to the exterior wall which I have gutted and I see no piping in the framing.

Something else that I found funny was that the drain for the sink and washer do not seem to connect to the main 3" in the picture you can see the washer drain and it runs towards the exterior wall, the sink drain seems to do the same as well.

Hi John...

This bathroom is a wet vented bathroom. Look at the picture below. You can see that the reason the vent doesn't go toward the outside wall is because it takes a left turn and picks up the lavatory drain. This drain acts to vent the shower and the toilet and also acts as the lavatory waste and vent.

The lavatory drain and vent should be increased to 2" to make this a legally wet vented bathroom. In terms of the washing machine, it must connect into the 3" drain a little further back underground, but it connects into the 3" drain.

Now, you can see that the new toilet drain runs into the old lavatory drain/vent....not a big deal, but a pain to be sure. Let me know where the washing machine is going in relation to all this and if it will connect into the 3" drain in this bathroom group or what? If you can draw me out everything in relation to each other I can draw it up pretty quick...

Also note that a toilet will rough in at 12" off the rough stud wall giving you an 11.5" rough off the finished wall and a nice tight toilet installation to the finished wall.



MARK

I broke up some more concrete and I discovered exactly what you had said.

Now the washing machine will be on the side where the toilet used to be and I will connect into the 3" pretty much where the toilet elbow is. Of course i will be reducing it to a 2" and it will have its own dry vent that I will T off from the lavatory vent.

Can I sit the toilet right over the 3" and use a T to connect to?

I found out that my drain for the lavatory is only 6 inches away from my 3" so I was thinking of putting some 45's on the lav drain to give me more room to shift to toilet of more toward the exterior wall.

Why would be connecting the toilet in its new location be a pain?

Hi John:

To wet vent this bathroom correctly... including the washer (individually vented as you noted) I would have you pipe it up as drawn below... see picture.

Here, you must use a WYE fitting to connect the toilet... NO sanitary tee fittings allowed on horizontal drain pipes. You could install the wye fitting into a street 90 (90 without a hub) or regular 90 for the toilet.

The toilet and shower will need to be wet vented by the lav. So you need to install a 3"x2" wye for this and then turn to pick up the shower using a 2" long sweep 90, or you can make a long sweep up using 2-45 degree fittings.

In terms of the washing machine and the 3" pipe... plumbing code would have you come out of the ground 3" and then install a 3" dandy cleanout (see pic.). Then reduce out of the 3" cleanout using a 3" cleanout using a 3" bushing and install 2" piping to drain for washer and run that 1.5" bushing and install 2" per foot. The sanitary tee fitting that comes off the lavatory vent needs to be installed so that the fitting is upside down... here, rain water that enters through the vent pipe must follow path that drains back to drains naturally, i.e. that is why the sanitary tee fitting is installed upside sown.

The toilet will no longer be a pain... not since I noticed that this all had to be repiped as drawn below... ;) So no issues there!

Let me know what you think...

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