This is my first online post so forgive me if I do not do this well.

My basement tub recently started to drain slowly. It has been snaked and various clog removers have been attempted. A plumber has been called and he spent three hours trying to remedy the problem to no avail. However, if I run a garden hose in the cleanout the drain clears well. With the garden hose running and the tub filled with any quantity water the tub will drain very quickly. Turn off the hose and the draining of the tub slows to a crawl where it takes about 1 minute to drain 1 inch of water.

The tub's drain flows under the tub (towards the back) about 3-4 feet at which point it turns downward into a cement floor. I assume this is the location of the p trap, but there is no way to tell without removal of several inches of concrete floor. In the wall at the back of the tub about six inches outside the outside edge of the tub is a lead pipe which I think is the kitchen drain (kitchen is 1 floor directly above). I assume this also doubles as the vent pipe, but I am not sure. I am also assuming that the bath tub drain as well as the bathroom sink tie into this lead pipe, but again I am unable to confirm without ripping out walls. I have looked outside at the roof and only see 1 vent pipe on the entire roof. It is located on the opposite side of the house 25 feet or so away. The house has two bathrooms and two kitchens. Assuming a venting issue, only the basement tub has a problem. This doesn't sound quite right

Also, the cleanout is outside the bathroom, about four inches from the floor and connected between the overflow drain and tub drain. I am able to insert the garden hose into the cleanout, navigate around a 45 degree bend and extend a total distance of close to 4 feet (I assume it reaches the bend of the assumed p trap).

Any ideas on how to resolve this issue? Thank you in advance.

Mr J



Edited 1 times.

I believe the tub drain is becoming air locked, the high pressure from the water hose breaks the air lock. It also sounds like you have a running trap or partial S-trap on the tub. An atmospheric vent pulled off the drain would most likely solve the problem. The trap needs to be directly under the waste and overflow assembly as well.

You are assuming many things, and the actual situation could be completely different. WE cannot make a diagnosis without seeing how the piping is arranged or what you are doing.

I have stated my assumptions. I would prefer to not to open walls or cut concrete (basement floor) at this point. As far as the drain from the tub goes I can tell you exactly what is there. I had removed the tub and looked at everything I could look at without performing a major demolition of the bathroom.

I will provide more details about the visible (when the tub is removed) plumbing. I redid much of it since the original plumbing was a mess and it was almost impossible to feed a snake into the system more than five or six inches.

The tub's drain flows to the left side (if you ar looking towards the front of the tub) about two inches into a tee (I believe it is called a sanitary tee - it curves toward the the downstream flow) and then turns left (towards the back of the tub) to the drain which is approximately 40-45" inches in length before turning downward into the concrete. At that point I don't know what happens so I assume there is a P-trap because there is no smell of sewer gases. On the third side of the sanitary tee connected to the drain is about three inches of pipe that meets a 45 degree elbow. The elbow is position to point both upwards and to the right towards the overflow. Connected to the 45 is another sanitary tee (again, the curved section is pointing downstream)to provide a clean out and overflow paths. The cleanout is approximately another 3" of pipe closed with a closeout cap. The overflow pipe connected to the same T as the cleanout has a small piece of pipe (1 to 2" long) before connecting to the overflow pipe. The overflow pipe is perfectly vertical for approx 4 - 5" where it connects to the tub.

There is about 3-1/4" clearance between the tub and the concrete floor. The 90 degree elbow (into the concrete and assumed trap) uses up almost all of this clearance. That is, the horizontal section of the 90 is about 3 to 3-1/8" above the concrete. At the tub's drain the clearance is only about 2-1/4" clearance (yes, the concrete floor is little higher in this area). Ideally, the p-trap should be instead here, but it wasn't due to lack of room. (The lack of p trap is the original installation that I inherited that has worked for years until a week or so ago). This kind of makes the 45" run of pipe run slightly backwards toward the tub's drain and I realize this may be part of the problem, but as this has been working for years and only recently started to drain slowly this cannot be the major source of the issue.

As for the plumbing in the wall for the bathroom sink or the kitchen drain / vent pipe I am not yet ready to destroy the entire bathroom to determine the connections.

As for an atmospheric vent I do not know what this is. If I went to a plumbing store they would know it by this name? Given the plumbing I described, would it still be possible to install this? Where is the best spot?

Thank you,
Mr J

I tried to draw the drain system using your description and got completely lost. But you imply that the tee and cleanout is above the floor ahead of the "P" trap, if so that is completely wrong.

I know that the plumbing configuration is not optimal. I understand that, ideally, the overflow should go straight down into a p trap with the tub drain connecting (via a tee) between the overflow and the p trap. That would be great, but that is not what I have. Knowing it has been functioning OK for several years and has just recently started to slow down what are the prime suspects for the cause?

I fully understand that If I could rip up six inches of concrete floor in a 5x10 bathroom and all the walls I could redo the lousy job done many years ago. But, that by itself does not explain what has happened in the last couple of weeks to cause the issue. So, even if I rip it up I may not find the problem. It may be a blockage in a vent pipe somewhere. The problem may be 20 feet aware from where I am looking.

In short, if I was installing the system from scratch with an open unfinished basement I could do it properly, but that is not an option. I have students renting the basement unit and I cannot have the bathroom out of commission for more than a day or so.

Knowing it is a poor installation, but a working one, for the most part what are the likely causes for the change? Clogged vent pipe? Maybe, but how come the bathroom sink isn't affected? Assuming a clogged vent pipe, how do I clear it? I have tried to provide all the info I can think of in the previous posts hoping someone has some ideas I can try short of ripping everything out and starting from scratch.

Thank you,



Edited 1 times.

Maybe I can provide a little clarity. I see the cleanout / overflow section may be tricky to picture.

If we start outside the bathroom with xray eyes and you can look at the tub through the wall the overflow pipe and cleanout pie will be nearest you. The overflow pipe is perfectly vertical about 4-5" in length. After 5" it goes into a 45 degree elbow angled down to the right. This 45 elbow joins a y (not a tee as previously stated). This y also connects to the clean out which I will describe shortly. The downstream part of the Y is pointing downish, slightly to the right but more towards the back of the tub. The downstream side of the y is another short piece of pipe that enters another 45 elbow. This output side of this 45 elbow is now perfectly horizontal and parallel to the sides of the tub. If there was no connection to the tub drain this 45 elbow would connect to a length of pipe about 45" inches long that runs parallel to the tub walls along the concrete floor where it then enters a 90 degree elbow pointing straight down into the concrete. However, there is a connection to the tub drain.

The tub drain is connected to a Tee inserted into the long length of pipe (mentioned above) about three inches from the last 45 degree elbow, between the elbow and the (assumed) p trap. The sanitary tee is completely horizontal. That is, all three pipes going in or out of the T are running along the floor. The connection to the tub drain is at 90 degrees to the long pipe run. The distance from the tub drain to the sanitary T is about 3" (two inches of pipe and 1/2" for the drain elbow and 1/2" for the sanitary tee.

Now we go back to the clean out. The cleanout can be seen clearly coming out of the wall without the need for xray vision. (ie, it is on the outside of the bathroom wall). It is angled downwards, approximately 45 degrees to the right and approximately 45 degrees to the back of the tub. As mentioned in the first paragraph the downstream side of the y connections to a 45 elbow that has its output parallel to both the floor and the tub walls so feeding a snake into this system is very simple: there is approximately 8 inches of pipe, one 45 degree bend and then 45" or so of pipe until the 90 degree elbow done into the concrete.

I hope this gives everyone a clearer picture of how the tub is connected.

However, this is not the real cause of the slow down. The configuration of the plumbing didn't change on its own two weeks ago to cause the slow draining. What are the likely causes?